Boiler Error Codes

Boiler Error Codes

    • Worcester Bosch

      Worcester Bosch CDI Classic Combi Boiler Error Codes

      Fault Description  System Behaviour
      A1 Water is leaking or the pump needs replacing or freeing due to the pump running dry.
      A7 The hot water negative thermistor coefficient (NTC) sensor is defective – the hot water sensor or connecting leads need checking.
      A8 Break communication to FX sensor controls electrical connections need checking.
      B1 Code plug not detected .
      C6 Fan speed too low – the fan lead and connector need checking and may need replacing.
      E2 Central heating (CH) water flow negative thermistor coefficient (NTC) sensor defective check CH flow NTC sensor and connection leads.
      E9 Safety temperature limiter in central heating (CH) flow has tripped the system pressure or safety temperature limiter needs checking
      EA Flame not detected due to a gas issue – the gas supply, power supply or igniter, electrode and lead need checking – contact a Gas Safe installer.
      F0 Internal error – electrical connector contacts or programmer interface module – check ignition leads are not loose.
      F7 Flame detected even though the appliance is switched off – check the electrode assembly is dry and the pcb and flue are clear.
      FA Flame detected after gas shut off – the gas valve needs checking – hire a Gas Safe installer.
      FD Reset button pressed by mistake – press reset button again.

      Worcester Bosch CDI Highflow Combi Boiler Error Codes

      Fault Description System Behaviour
      A1 Pump dry run detection or pump is running in air the system pressure needs checking
      A5 Tank negative thermistor coefficient (NTC) defect
      A7 Domestic hot water (DHW) negative thermistor coefficient (NTC) defect
      A8 Energy Management System (EMS) communication error
      B1 Code plug not detected
      B2, B3, B4, B5, B6 Data error
      B7 Burner control error
      C6 Fan defect
      D3 External temperature limiter
      D5 Condensate pump failure
      D6 Internal heat bank overflow
      EA Flame not detected
      E2 Primary negative thermistor coefficient (NTC) defect
      E9 Safety temperature limiter in central heating (CH) flow stat tripped
      F0 Internal error
      F1 ROM fault
      F7 Flame detected after appliance has been shut off
      FA Flame detected after gas shut off
      FD Reset button pressed – try pressing the reset button again

      Worcester Bosch CDi Compact / Greenstar 25/30 Si Combi / Greenstar 27/30 I system Boiler Error Codes

      Fault Description System Behaviour
      T1 Ignition test – checking the igniter spark
      T2 Fan test – checking the basic fan
      T3 Pump test – checking the basic pump
      T4 Three way valve test
      T6 Ionisation oscillator test
      9A 362 error – incorrect HCM fitted
      9U 233 Heat Control Module (HCM) error – problem with code plug
      B7 257 Internal error – possible control board problem
      C6 215 Fan problem – fan running too fast
      C7 214 Fan problem – fan not running
      D1 240 Return sensor error – sensor may be wet or damaged
      E2 222 Flow sensor short circuit error
      E5 218 Flow temperature too high
      E9 219 Safety sensor fault – temperature too high, sensor short circuit or open circuit
      EA 227 No flame detected or flame signal loss during operation
      F0 237 Internal error
      F7 228 Flame error – false flame or flame detected before burner started
      FA 306 False flame fault – flame detected after burner stop
      FD 231 Mains power fault – electrical power interruption
      FA 364 Gas valve EV2 leak test failed – gas valve leak
      FB 365 Gas valve EV1 leak test failed
      A1 281 Pump stuck or running with air in the system
      C1 264 Airflow stopped during operation
      C4 273 Airflow present during last 24 hour
      D1 240 Return sensor short circuit
      D4 271 Temperature difference between flow and safety sensor exceeds limit
      E9 224 Max thermostat activated – flue gas thermostat overheat
      EA 227 No ionisation detected after ignition
      EF 349 Central heating boil detected – boiler operating at minimum burner load with temperature difference greater than 18°C between Flow & Return.
      NO CODE 212 Safety or flow temperature rising too fast

      Worcester Bosch CDi Classic Regular Boiler Error Codes

      Fault Description System Behaviour
      B1 Code plug not detected
      C6 Fan speed too low
      E2 Central heating (CH) flow negative thermistor coefficient (NTC) sensor defective
      E9 Safety temperature limiter in central heating (CH) flow has tripped
      EA Flame not detected
      F0 Internal error
      F7 Flame detected even though appliance switched off
      FA Flame detected after gas shut off
      FD Reset button pressed by mistake

      Worcester Bosch Greenstar I System / Combi Boiler Error Codes

      Fault Description System Behaviour
      226 Service tool has been connected in the blocking error history menu
      FD 231 The power has been interrupted during a lockout
      C7 214 Fan does not run during the start up phase – fan harness connector needs checking
      C6 215 Fan speed too high – check the fan harness and connector
      C7 216 Fan speed too low – check the fan harness and connector
      C7 217 Fan has stopped during appliance operation
      C1 264 Fan stopped during operation
      C4 273 Continuous fan operation for the last 24 hours – appliance temporarily blocked
      E2 222 Flow temperature sensor shorted
      E2 233 Flow temperature sensor disconnected
      E9 276 Primary flow temperature exceeded 95°c
      E2 350 Flow temperature sensor shorted
      E2 351 Flow temperature sensor disconnected
      FA 306 Ionisation detected after the gas valve closed
      EA 227 No ionisation detected after ignition
      F7 228 Isioniation current detected before burner start
      EA 229 Loss of ionisation signal during operation
      EA 261 Heat control module (HCM) potentially defective – reset the appliance
      9U 233 Control box or heat control module (HCM) is defective or loose, the HCM needs to be checked
      C4 237 Control box or heat control module (HCM) is defective
      F0 238 Gas valve or control box error – gas valve coils need checking
      F0 239 Control box or the heat control module (HCM) is defective – the control box connections need checking
      F0 242 Control box or the heat control module (HCM) is defective – the HCM and control box connections need to be checked
      B7 257 Control box or the heat control module HCM) is defective- the HCM and control box connections need to be checked
      F0 258 Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
      EH 258 Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
      F1 259 Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
      F0 262 Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
      F1 263 Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
      F0 272 Control box or the heat control module (HCM) is defective – control box and connections need checking or HCM might not be inserted properly and need replacing
      F0 280 Control box or the heat control module (HCM) is defective – control box and connections need checking or HCM might not be inserted properly and need replacing
      F0 290 Control box is defective – HCM needs checking as it might not be inserted properly or need replacing
      328 Internal error with the mains voltage – frequency may be inconsistent
      235 Incompatible heat control module (HCM) software versions – control box needs latest software
      356 Low mains voltage – the voltage may be interrupted or inconsistent and needs checking
      360 Heat control module (HCM) invalid – the inserted HCM does not correspond with the control box
      A8 362 Low mains voltage – the voltage may be interrupted, inconsistent or heat control module (HCM) invalid
      CC 800 Outdoor sensor defect available when accessory outdoor sensor is connected
      A1 281 Pump stock or running dry
      E9 224 Flue or high limit thermostat activated
      D4 341 Primary flow temperature rising too fast

      Worcester Bosch GB162 Boiler Error Codes

      Fault Description System Behaviour
      208 The boiler is in chimney sweep mode
      200 The boiler is in heating mode
      201 The boiler is in domestic hot water (DHW) mode
      202 The boiler is waiting – there was a heat demand from the on off or modulating control
      203 The boiler is on standby
      204 The boiler is waiting – the actual temperature is higher than the calculated or selected boiler temperature
      212 The temperature recorded by the flow temperature sensor or the safety sensor is rising too quickly
      226 Diagnosis tool was connected and is now locked out
      260 The flow temperature sensor is not detecting a rise in temperature following a burner start
      265 The boiler is waiting in response to a heat demand – the boiler regularly switches to partial load
      268 Component test phase
      270 The boiler is modulating upwards
      283 The boiler is preparing for a burner start – the fan and pump are activated
      284 The gas valve is switched
      305 The boiler is waiting for domestic hot water (DHW) operation to end
      235 The KIM (boiler identification module) is too new for the burner control unit
      360 The KIM that has been fitted is not compatible with the burner control unit
      9A 361 The burner control unit that has been fitted is not compatible with the KIM (boiler identification module)
      9U 233 The burner control unit or KIM (boiler identification module) is faulty
      A3 317 Short circuit in the flue gas temperature sensor contacts
      B7 257 The burner control unit or the KIM (boiler identification module) is faulty
      C1 264 No control signal or power supply to the fan during operation
      C4 273 The boiler was switched off for a maximum of 2 minutes because it had been operating continuously for more than 24 hours
      C6 215 The fan speed is too high
      C6 216 The fan speed is too low
      C7 214 The fan does not run during the start phase
      C7 217 The fan speed is irregular when starting up
      CE 207 Water pressure is too low
      CE 266 Pump test failed
      D1 240 The contacts of the boiler return temperature sensor have been short circuited
      D1 241 The contacts of the boiler return temperature sensor have been interrupted
      D3 232 The external switching contact has opened
      D4 213 The actual temperature recorded by the flow temperature sensor or return temperature sensor is rising too quickly
      D4 271 Actual temperature differential between flow and safety temperature sensor is too high
      D4 286 The boiler return temperature sensor has detected a return temperature higher than 105°c
      E2 222 Short circuit in the flow temperature sensor contacts
      E2 223 The flow temperature sensor contacts have been interrupted
      E5 218 The temperature captured by the flow temperature sensor exceeded 105°c
      E9 210 The temperature measured by the flue gas sensor is too high and is open
      E9 219 The safety temperature sensor has captured a temperature in excess of 105°C
      E9 220 The contacts for the safety temperature sensor have shorted or the safety temperature sensor has detected a temperature higher than 130°c
      E9 224 The contacts of the safety temperature sensor have been interrupted
      E9 276 The temperature flow sensor has measured a temperature in excess of 95°c
      E9 277 The safety temperature sensor has measured temperature in excess of 95°c
      E9 285 The boiler return temperature sensor has measured a temperature higher than 95°c
      E9 318 The flue gas temperature sensor contacts have been interrupted
      EA 227 An insufficient ionisation current was measured following ignition of the burner
      EA 229 The ionisation current detected by the system during the burning phase was insufficient
      EA 234 The contacts of the gas valve have been interrupted
      EA 261 The burner control unit is faulty
      EA 269 The ignition device has been activated for too long
      F0 238 The burner control unit KIM (boiler identification module) is faulty
      F0 239 The burner control unit KIM (boiler identification module) has an error. Cabling might have poor contact breaks and pinching or
      the plug and wiring of the burner control unit needs checking, also check the operating characteristics of the boiler by replacing the burner control unit.
      F0 242, F0 243. F0 244.
      F0 245, F0 246. F0 247, F0 248,
      F0 249, F0 250, F0 251, F0 252,
      F0 253, F0 255, F0 259, F0 263,
      F0 267, F0 272
      The burner control unit (KIM) is faulty – the wiring of the burner control unit needs checking, also
      check the operating characteristics of the boiler by replacing the burner control unit.
      F0 278 The sensor test has failed – cabling and plug sensors need checking
      F0 279 The burner control unit, or KIM, is faulty – control unit may need replacing
      F0 280 The burner control unit is faulty
      F0 287 The burner control unit, or KIM, has an error
      F0 290 The burner control unit, or KIM, is faulty
      F7 228 An ionisation current was measured before the burner started
      F7 328 A brief power failure has occurred
      FA 306 An ionisation current was measured after the burner went out
      FD 231 The mains voltage was interrupted during an interlocking fault
      EC 256 The burner control unit has an error
      EH 258 The burner control unit is faulty – check the plug and wiring of the burner control unit.
      H07 The current water pressure is too low, limiting the performance in heat mode as well as domestic hot water (DHW) mode
      HrE The boiler keeps resetting
      rE The boiler resets
      Worcester Bosch CDI Highflow Combi Boiler Error Codes
      A light on your boiler will flash to indicate that there is a fault. Depending on the type of fault, the light will flash in a different sequence.
      There will be 4 quick flashes followed by a 5 second gap when the light is off and finally a series of longer flashes. The number of long flashes tells you which fault the boiler has.
      Fault Description System Behaviour
      Light off No boiler demand
      Light on Heating demand on boiler is OK
      1 flash 5 seconds off No ionisation detected after ignition
      2 flashes 5 seconds off Loss of ionisation signal during operation
      3 flashes 5 seconds off Gas valve error
      4 flashes 5 seconds off First safety timing error / ignition timing error
      5 flashes 5 seconds off Ionisation detected after burner stopped
      Gas valve EV2 leak test failed
      Gas valve EV1 leak test failed
      Ionisation current detected before burner start
      Gas valve error
      Ionisation sensor shorted
      4 flashes 5 second gap 1 long flash Sensor test failed
      4 flashes, 5 second gap, 2 long flashes Safety temperature too high
      4 flashes, 5 second gap, 3 long flashes Max safety thermostat activated
      4 flashes, 5 second gap, 4 long flashes Return temperature too high
      4 flashes, 5 second gap, 5 long flashes Flow temperature too high – supply sensor exceeded 110°c
      1 long flash, 4 quick flashes,
      5 second gap, 1 long flash, 4 quick flashes
      Heating control module (HCM) defective
      2 long flashes, 4 quick flashes,
      5 second gap, 2 long flashes, 4 quick flashes
      Fan running too fast
      Fan running too slow
      No airflow after defined period of time
      Fan not running
      3 long flashes, 4 quick flashes,
      5 second gap, 3 long flashes, 4 quick flashes
      Mains voltage interrupted after locking error
      4 long flashes, 4 quick flashes,
      5 second gap, 4 long flash, 4 quick flashes
      Internal control board faults
      5 long flashes, 4 quick flashes,
      5 second gap, 5 long flash, 4 quick flashes
      All other miscellaneous faults – reset the boiler by turning the control knob anti-clockwise to the reset position
      Worcester Bosch Greenstar Ri Boiler Error Codes
      Fault Description​ System Behaviour
      No light No power at control board
      Light on Appliance on but not operating during demand
      Slow flash ( mostly off flashes on) Ignition lockout
      Slow flash ( mostly on flashes off) Flue overheat or heat exchanger overheat
      Fast flash Volatile lockout sensor fan or code plug
      2 pulses Check service mode switch is in minimum position
      5 pulses Check service mode switch is in max position
      Worcester Bosch Error Code EA 229 or D5
      If you’re seeing the error code EA 229 or D5 on your Worcester Bosch boiler, this means that the condensate pipe is frozen.
      This happens due to the condensate pipe running outside, however this is an issue that you could fix yourself if you feel confident enough, you can find out how in our handy guide.
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    • Glow Worm
      Glow-worm Boiler Error Codes
      Boiler Model Fault Code Cause of Problem
      Betacom Red LED on Lockout – low water pressure (increase pressure to 1.5bar) and reset boiler
      Betacom Red LED flashing Overheat – check both overheat stats
      Betacom Yellow LED flashing Turn domestic hot water (DHW) control knob into temperature
      range and turn central heating (CH)
      temperature control knob into power (reset position) and wait for minimum of 30
      seconds before turning into either summer or temperature position
      Betacom Yellow LED on Flame present on the burner
      Betacom Green LED on Boiler ready for operation
      Betacom Green LED off No power to boiler – Check for 230volts into the appliance,
      check fuse on printed circuit board (PCB)
      Betacom / Ultracom₂ cxi / sxi / 35 F00 / F10 / F71 Flow heating temperature sensor fault
      Betacom / Ultracom₂ cxi / sxi / 35 F01 / F11 Return heating temperature sensor fault
      Betacom / Ultracom₂ cxi / sxi / 35 F20 Overheating fault
      Betacom / Ultracom₂ cxi / sxi / hxi / 35 / Flexicom cx / hx / sx F9 / F22 Low water pressure (or ignition temperature rise too slow)
      Betacom / Ultracom₂ cxi / sxi / 35 F26 / F77 Fault in gas valve
      Betacom / Ultracom₂ cxi / sxi / 35 / CI / hxi / Xtramax HE F27 / F16 Flame detection fault
      All Boilers F28 / F1 / F4 Ignition fault (flame detection)
      Betacom / Ultracom₂ cxi / sxi / 35 F29 Loss of flame during operation
      Betacom / Ultracom₂ cxi / sxi / 35 F32 Incorrect air pressure
      Betacom / Ultracom₂ cxi / sxi / 35 F49 EBUS voltage fault
      Betacom / Ultracom₂ cxi / sxi / 35 F61 / F62 / F63 / F64 / F65 / F67 Fault in the main board
      Betacom / Ultracom₂ cxi / sxi / 35 F68 Fluctuation of flame signal
      Betacom / Ultracom₂ cxi / sxi / 35 F70 User interface incompatible with the main board
      Betacom / Ultracom₂ cxi / sxi / 35 F72 / F84 Permanent temperature difference between flow and return heating sensors
      Betacom / Ultracom₂ cxi / sxi / 35 F73 / F74 Heating circuit pressure sensor fault
      Betacom / Ultracom₂ cxi / sxi / 35 F76 Thermal fuse fault
      Betacom / Ultracom₂ cxi / sxi / 35 F83 Thermal fuse fault
      Betacom / Ultracom₂ cxi / sxi / 35 F85 Flow and Return heating sensor fault
      Betacom / Ultracom₂ cxi / sxi / 35 F86 Underfloor heating contact fault
      All Boilers ERR / F12 / F18 User interface fault
      Betacom c Temperature 30 flashing Fault on central heating (CH) thermistor
      Betacom c Temperature 40 flashing Fault on DHW thermistor
      Betacom c Temperature 50 flashing Fault on outside sensor
      Betacom c Temperature 60 flashing Low system pressure
      Betacom c Temperature 70 flashing Fault on APS
      Betacom c Temperature 80 flashing Overheat open circuit
      Betacom c Temperature 90 flashing Flame or gas failure
      Compact e / s No DHW Check dhw microswitch / Check external controls, Please test for 230V on switch live contact
      Compact e / s No C/H Check dhw microswitch if dhw demand led is lit / Check external controls, Please test for 230V on switch live contact
      Compact e / s No C/H but boiler is firing Check diverter motor and cartridge / Check external controls, Please test for 230V on switch live contact
      Compact e / s Boiler locks out within 10 seconds Check pump proving switch, air pressure switch and overheat state / Check pump proving switch, air pressure switch and overheat stat
      Compact e / s Poor burner pressure Check burner pressure/ignition adjustment pots on PCB
      Ci Range (plus) / Si range F2 Fan/APS
      All Boilers F5 Overheat Fault
      All Boilers F6 Central heating flow thermistor
      All Boilers F7 Domestic hot water thermistor
      All Boilers F8 Tank thermistor fault
      sxi / si / ci (plus) range / Xtramax HE F9 Water pressure sensor fault (please contact GW technical department for
      further information)
      All boilers F10 Central return flow thermistor
      All boilers F11 Main board connection fault
      Ci (plus) / cxi / hxi / si / sxi range F12 Connection fault between main printed circuit board (PCB) and display PCB
      Ci (plus) / cxi / hxi / si / sxi range F13 Main PCB connection fault
      Ci (plus) / cxi / hxi / si / sxi range F14 Central heating flow temperature > 95 degrees
      Ci (plus) / cxi / si / sxi range F15 Gas valve stepper motor fault
      Ci (plus) / cxi / hxi / si / sxi range / Xtramax HE F17 Power supply is less than 170v
      Ci (plus) / cxi / hxi / si / sxi range / Xtramax HE F19 Central heating thermistor unplugged
      Ci (plus) / cxi / hxi / si / sxi range / Xtramax HE F20 Software incompatibility
      cxi / hxi / sxi range / Flexicom cx F24 Central heating return temperature > 90 degrees
      cxi / hxi / sxi / Xtrafast 96/120 / Xtrafast 96/120E1 F25 / F26 / F11 Poor circulation
      ci range F3 Air fault
      ci range F3 Air fault
      cxi / sxi / hxi range/ Xtramax HE F2 / F3 Fan
      cxi / sxi range / Flexicom cx / hx / sx /
      hxi / Ultracom cxi / cx / hxi / sxi / Ultrapower sxi
      F3 Fan unable to reach ignition speed
      Flexicom cx / hx / sx / hxi / Ultracom cxi / cx / hxi / sxi F9 Water pressure sensor fault, blocked flow filter or pump fault
      Flexicom cx / hx / sx F11 Flow and or return thermistor fault
      Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HE F13 PCB memory or sensing fault
      Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HE F14 Gas valve control defective
      Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HE F15 E-bus voltage failure
      All boilers F25 / F23 Circulation fault
      Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi F43 Generic error
      Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi F70 Software incompatible
      Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi F73 Unable to see pump activate
      Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi F77 Condensate pump error (optional)
      hxi range F9 Earlier models only (please contact GW technical department for further
      information)
      hxi range F9 Earlier models only (please contact GW technical department for further
      information)
      Ultracom₂ 35 Store F02 / F12 Hot water temperature sensor fault
      Ultracom₂ 35 Store F03 / F13 / F79 Storage tank temperature sensor fault
      Ultracom₂ 35 Store F81 Overheating of hot water circuit
      All Ultracom No display or Er loose connection X51
      Xtramax HE Range F24 Cental heating return temperature > 90 degrees
      Xtramax HE Range F25 Maximum temperature rise slope
      Xtramax HE Range F26 Maximum delta temperature
      Xtrafast 96/120 Range F00 No fault/td>
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F00 No fault
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F02 Air flow fault
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F05 Overheating
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F06 Central heating thermistor/wiring fault
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F08 Storage vessel thermistor/wiring fault
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F09 System pressure sensor fault
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F10 Fan fault
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F13 Main printed circuit board (PCB) fault
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F14 Central heating flow temperature > 97 degrees
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F15 Gas mechanism fault
      Xtrafast 96/120 Range / Xtrafast 96/120E1 Range F20 Communication fault

      Glow-worm Energy Boiler Range Error Codes

      Fault Code Cause of Problem
      F.00 Flow temperature sensor
      F.00 Flow temperature sensor
      F.10 Flow temperature sensor short circuit
      F.11 Flow temperature sensor short circuit
      F.12 and F.91 Cylinder temperature sensor short circuit
      F.13 Domestic hot water cylinder temperature sensor short circuit
      F.20 Safety switch-off – overheating temperature reached
      F.22 Safety switch-off – low water pressure in the boiler
      F.23 Safety switch-off – temperature difference too great (NTC1/NTC2)
      F.24 Safety switch-off – temperature rise too fast
      F.25 Safety switch-off – flue gas temperature too high
      F.27 Safety switch-off – fault in flame detection
      F.28 Ignition unsuccessful when starting up
      F.29 Flame loss
      F.32 Fan frost protection function active – fan speed outside the tolerance values
      F.33 Fan frost protection function active – air pressure switch fault
      FA9 eBUS fault – voltage too low
      F.61 Gas valve control system fault
      F.82 Gas valve switch-off control fault
      F.83 EEPROM fault – electronics defective
      F.64 Electronics/sensor/analogue-to-digital converter fault
      F.85 Electronics temperature too high
      F.67 Value sent back by ASIC is incorrect (flame signal)
      F.88 Unstable flame (analogue input), underfloor heating contact or gas valve fault
      F.70 Invalid product code (DSN)
      F.71 Flow/return temperature sensor
      F.72 Deviation in the water pressure sensor/return temperature sensor
      F.73 Water pressure sensor not connected or has short-circuited
      F.74 Electrical problem in the water pressure sensor
      F.75 Pressure sensor fault
      F.78 The safety cut-out in the primary heat exchanger is defective
      F.77 Fault: Condensate or smoke
      F.78 Interruption to domestic hot water (DHW) outlet sensor at external controller
      F.83 Burner temperature sensor fault
      F.84 Flow/return temperature sensor fault
      F.85 Temperature sensor fault
      F.87 Electrodes fault
      F.89 Pump fault
      Connection No communication between the printed circuit board (PCB) and the user interface
      Glow-worm Error Codes F1, F4, F28 or F29
      If you are seeing the error codes F1, F4 F28 or F29 on your boiler there’s an issue with your condensate pipe.
      This error appears when your pipe is frozen, which can happen during the cold months as it runs outdoors.
      You can fix this issue yourself if you feel confident enough, otherwise call an engineer, by thawing out the
      pipe which you can find out how to do with our handy guide to thawing a condensate pipe.
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    • Vaillant
      Vaillant Turbomax Plus 824/828E
      Fault Code Possible Cause Meaning
      F.00 NTC FAULTS This means that your Flow NTC (Negative Temperature Coefficient Thermostat)
      cable is either defective or broken and needs to be replaced
      F.01 NTC FAULTS (feed temperature sensor)
      – faulty connection and open circuit.
      This means that your Flow NTC (Negative Temperature Coefficient Thermostat)
      cable is either defective or broken and needs to be replaced
      F.10 NTC FAULTS (feed temperature sensor) – short circuit
      F.11
      F.13 NTC FAULTS (feed temperature sensor) – short circuit
      F.20 NTC FAULTS (feed temperature sensor) Your boiler has exceeded the maximum temperature
      and needs to be allowed to cool down
      F.22 DRY FIRE, LOW WATER IN SYSTEM/OVERHEAT This means that there’s either no water in your system,
      you have a defective pump or the pump lead is defective
      F.24 LOW WATER, OR PUMP FAILURE/BLOCKAGE Your pump could be obstructed, running at low capacity,
      or there could be air trapped in your appliance.
      Additionally, the pressure in your system might be too low.
      F.28 NO IGNITION/IGNITION PROBLEM This means there’s either insufficient gas in the system, a defective electrode,
      ignition lead or electronic ignitor
      F.29 FLAME EXTINGUISHED. FAN/FLUE PROBLEM/GAS Your flame, or pilot light has gone out. Check your flue duct or gas supply to
      see if there is a problem there.
      F.60 GAS VALVE CONTROL – DEFECTIVE Your cable loom which connects to your gas valve might have short circuited.
      Alternatively, you could have a defective gas valve assembly or electronic control system.
      F.61 GAS VALVE CONTROL – DEFECTIVE Your cable loom which connects to your gas valve may have short circuited.
      Alternatively, you could have a defective gas valve assembly or electronic control system.
      F.62 DEFECTIVE GAS VALVE CLOSURE MECHANISM Your boiler has exceeded the maximum temperature and needs to be allowed to cool down
      F.63 EEPROM (Electrically Erasable Programmable Read-Only Memory) ERROR This is an electronic fault within your system.
      F.64 ELECTRONIC SYSTEM/SENSOR FAULT Your flow or back flow NTC has suffered a short circuit, or an electronic fault
      F.65 ELECTRONIC SYSTEM TEMPERATURE TOO HIGH This can happen because of an external heat source or an electrical fault
      F.67 ELECTRONIC FAULT IN FLAME SYSTEM

      Vaillant EcoMax Pro 18/28E

      Fault Code​ Possible Cause
      F.1 Lack of gas, a fault with the ignition or flue or you may need to adjust the
      gas valve or replace a defective electrode lead.
      F.4 Ignition fault.
      F.5 The system has suffered a fault due to overheating.
      F.6 Your flow NTC has developed a fault.
      F.17 Check the polarity of your system.
      F.24 Pump-related faults – the pump could have failed, it may have over run or
      there could be an issue with the airlock
      Vaillant Ecomax Pro 828E
      Fault Code Possible Cause
      F.00, .04, .05, .10, .14, .15 All of these are NTC faults, and are best resolved by first changing all NTC
      to make diagnosis earlier.
      F.21 The pilot flame has failed.
      F.22 There is insufficient water in your system.
      F.11 A blockage in the appliance is preventing the system from flowing as it
      should.
      F.12 A blockage in the appliance is affecting the system’s pressure.
      F.13 The appliance is blocked because of a water deficiency.

      Vaillant EcoTEC 65kW Error Codes

      Fault Code Possible Cause
      S.O Heating issue, no heat demand
      S.1 Fan start-up error
      S.2 Pump flow error
      S.3 Heating mode error – ignition problem
      S.4 Heat mode – burner on error
      S.6 Heating mode – fan overrun error
      S.7 Heating mode – pump overrun error
      S.8 Heating remaining cut off for XX amount of time
      S.31 No heat demand summer operating mode
      S.34 Heating mode frost protection error
      S.20 Hot water requirement error
      S.22 Hot water handling pump flow error
      S.24 Hot water operation burner is on
      S.85 Service message quantity of circulation water

      Vaillant EcoTEC Pro / EcoTEC Plus Error Codes

      Fault Code Possible Cause
      F.00 / F.0 Flow temperature sensor interruption
      F.01 / F.1 Return temperature sensor interruption
      F.10 Flow NTC short circuit
      F.11 Return NTC short circuit
      F.20 Safety switch off temperature limiter
      F.22 Safety switch off low water pressure
      F.23 Safety switch off temperature difference too great
      F.24 Safety switch off temperature is rising to fast
      F.25 Safety switch off flue gas temperature too high
      F.26 Error with gas valve – possible no function
      F.27 Safety switch off flame simulation
      F.28 Failure during start up – ignition unsuccessful to start
      F.29 Failure during operation – re-ignition unsuccessful
      F.32 Fan error
      F.49 eBUS error – possible short circuit
      F.61 Error with gas valve regulation
      F.62 Error with gas valve – switch off delay
      F.63 EEPROM error
      F.64 Electronics / NTC error
      F.65 Electronic temperature error could be overheating due to external
      influences
      F.67 Electronics flame signal error
      F.68 Unstable flame signal error air in gas
      F.70 Invalid device specific number (DSN)
      F.71 Flow NTC error – flow temperature sensor signal constant value
      F.72 Flow return NTC error – temperature difference too great
      F.73 Water pressure sensor signal in the wrong range, it is too low
      F.74 Water pressure sensor signal outside correct range, the sensor signal is
      too high
      F.75 Error with pressure – no pressure change detection when starting the
      pump
      F.76 Overheating protection on – primary heat exchanger has responded
      F.77 Flue non return flap condensate pump error
      F.78 Interruption to DHW outlet sensor at external controller
      F.83 Flow and or return temperature sensor error
      F.84 Error with flow/return temperature sensor temperature changing error
      F.85 Error with flow and return temperature, sensor incorrectly fitted
      CONNECTION No communication with the PCB

      Vaillant EcoTEC Pro / EcoTEC Plus Error Codes

      Fault Code Possible Cause
      S.00 Heating mode error – no heat demand
      S.01 Heating mode fan start-up
      S.02 Heating mode error – water pump running
      S.03 Heating mode – ignition sequence error
      S.04 Heating mode – burner ignited
      S.06 Heating mode – fan overrun error
      S.07 Heating mode – pump overrun error
      S.08 Heating remaining cut off time xx minutes
      S.10 Hot water demand via impeller sensor
      S.11 DHW mode fan start up error
      S13 DHW mode ignition error
      S.14 Hot water demand via fan sensor error
      S.15 DHW mode pump and fan overrun
      S.16 DHW mode – fan overrun error
      S.17 DHW mode – pump overrun error
      S.20 DHW mode – burner on error
      S.21 DHW mode – fan start up error
      S.22 DHW demand – error pump running
      S.23 DHW ignition error
      S.24 DHW mode – burner error
      S.25 DHW mode – pump or fan overrun error
      S.26 DHW mode – fan overrun
      S.27 DHW mode – pump overrun
      S.28 Hot water burner anti-cycling time
      S.30 Room thermostat is blocking heating mode
      S.31 No heat demand boiler in summer operating mode
      S.32 Waiting period because of fan speed deviation
      S.34 Heating mode frost protection error
      S.39 Burner off contact has been triggered this could be because of contact
      thermostat or condensate pump
      S.40 Comfort safety mode active
      S.41 Water pressure > 2.8 bar
      S.42 Flue non return flap return signal blocks burner operation
      S.46 Comfort safety mode flame loss at minimum load
      S.53 Boiler is in waiting period of modulation f block function due to water
      shortage
      S.54 Boiler is in waiting period of operation, blocking function as a result
      S.57 Waiting period comfort safety mode
      S.58 Modulation limitation due to noise / wind error
      S.61 Gas family check unsuccessful

      Vaillant EcoTEC Plus Regular Gas Boiler Error Codes

      Fault Code Possible Cause
      S.20 Warnstar demand
      S.21 Fan running
      S.22 Pump running
      S.23 Ignition sequence
      S.24 Burner ignited
      S.25 Fan and water pump running
      S.26 Fan overrun
      S.27 Pump overrun
      S.28 Anti-cycling mode
      S.30 No heating demand from external controls
      S.31 Central heating thermostat knob turned off
      S.32 Heat exchanger antifreeze active as fan speed variation is too high
      S.34 Anti-frost mode is active
      S.36 Not heating demand form low voltage
      S.41 Water pressure greater than 2.9 bar
      S.42 Response from accessory module or defective condensate pump is
      blocking burner operation
      S.53 Appliance is within the waiting period of the block operation function due
      to water shortage
      S.54 Appliance is within the waiting period of the block operation due to water
      shortage
      S.96 Return sensor error
      S.98 Flow return sensor check is running demand is block
      D.0 Heating part load error
      D.1 Water pump overrun – time for heat mode
      D.2 Max burner anti-cycling period at 20c flow temperature
      D.3 Hot water flow temperature reading
      D.4 Current temperature for warm stat sensor
      D.7 Warm start temperature target value
      D.8 External controls heat demand
      D.9 Flow target temperature from external analogue regulator terminal
      D.10 Status internal heating pump error
      D,11 Status external heating pump error
      D.12 Cylinder charging pump via accessory module
      D.13 Hot water circulation pump
      D.22 Hot water demand
      D.23 Summer/Winter function
      D.25 Hot water activation via ebus control
      D.30 Control signal for both gas valves
      D.33 Fan speed target value
      D.34 Fan speed actual value
      D.36 Hot water flow sensor
      D.40 Flow temperature target value
      D.41 Return temperature actual value
      D.44 Digitised ionisation potential error
      D.47 Outside temperature with weather compensator – Vaillant controller only
      D.76 Remaining burner anti-cycling time in min
      D.90 Digital regulator status
      D.91 DCF status with connected external probe
      D.97 Activation of the second diagnostic level
      D.17 Heating glow return regulation
      D.18 Pump mode return
      D.19 Operating modes of the two speed heating pump
      D.20 Maximum set value for target cylinder
      D.27 Switching accessory relay 1
      D.28 Switching accessory relay 2
      D.50 Offset for minimum speed
      D.51 Offset for maximum speed
      D.58 Activation of solar reheating
      D.60 Number of safety temperature cut off
      D.61 Number of unsuccessful lockouts
      D.64 Average ignition times
      D.65 Maximum ignition time
      D.68 Unsuccessful ignitions in the first attempt
      D.69 Unsuccessful ignition for the second time
      D.70 Set diverter valve position
      D.71 Maximum setting of heater control knob
      D.72 Pump overrun time after warm start
      D.73 Off set for warm start target value
      D.75 Maximum charging time for a storage without own controller
      D.77 Limitation of cylinder charging in output in kW
      D.78 Limitation of cylinder charging temperature in c
      D.80 Operating hours heating
      D.81 Operating hours hot water generation
      D.82 Burner start up in heating mode
      D.83 Burner start up in hot water mode
      D.84 Maintenance indicator – number of hours until the next maintenance
      D.93 DSN appliance variant setting
      D.96 Factory setting

      Vaillant EcoTEC Plus Gas Boiler Error Codes

      Fault Code Possible Cause
      P.00 The heating circuit and hot water circuit are purged
      P.01 Maximum load test program error
      P.02 Minimum load test program
      P.06 Filling mode test program
      Vaillant EcoTEC Gas Boiler Error Codes
      Fault Code Possible Cause
      D.0 Heating part load error
      D.1 Water pump overrun – time for heat mode
      D.2 Max burner anti-cycling period at 20c flow temperature
      D.3 Hot water flow temperature reading
      D.4 Current temperature for warm stat sensor
      D.5 Set value of flow temperature or target value of return
      D.7 Warm start temperature target value
      D.8 External controls heat demand
      D.9 Flow target temperature from external analogue regulator terminal
      D.10 Status internal heating pump error
      D,11 Status external heating pump error
      D.12 Cylinder charging pump via accessory module
      D.13 Hot water circulation pump
      D.15 Pump speed actual value
      D.22 Hot water demand
      D.23 Summer/Winter function
      D.24 Not relevant
      D.25 Hot water activation via eBus control
      D.30 Control signal for both gas valves
      D.33 Fan speed target value
      D.34 Fan speed actual value
      D.35 Not relevant
      D.40 Flow temperature target value
      D.41 Return temperature actual value
      D.44 Digitised ionisation – potential error
      D.47 Outside temperature with weather compensator – Vaillant controller only
      D.76 Remaining burner anti-cycling time in min
      D.90 Digital regulator status
      D.91 DCF status with connected external probe
      D.97 Activation of the second diagnostic level
      D.98 Telephone a heating engineer
      D.14 Pump speed target value
      D.17 Heating flow return regulation
      D.18 Pump operating mode
      D.20 Maximum set value for target cylinder
      D.26 Additional relay control ecoTec
      D.27 Switching accessory relay 1
      D.28 Switching accessory relay 2
      D.50 Offset for minimum speed
      D.51 Offset for maximum speed
      D.60 Number of safety temperature cut offs
      D.61 Number of unsuccessful lockouts
      D.64 Average ignition times
      D.65 Maximum ignition time
      D.67 Remaining burner anti-cycling time
      D.68 Unsuccessful ignitions in the first attempt
      D.69 Unsuccessful ignition for the second time
      D.70 Set diverter valve position
      D.71 Maximum setting of heater control knob
      D.72 Pump overrun time after warm start
      D.75 Maximum charging time for a storage without own controller
      D.77 Limitation of cylinder charging in output in kW
      D.78 Limitation of cylinder charging temperature in celsius
      D.80 Operating hours heating
      D.81 Operating hours hot water generation
      D.82 Burner start up in heating mode
      D.83 Burner start up in hot water mode
      D.84 Maintenance indicator – number of hours until the next maintenance
      D.93 DSN appliance variant setting
      D.96 Factory setting
      Vaillant Error Codes F28 and F29
      If your Vaillant boiler is showing either error code F28 or F29 then the condensate pipe
      has frozen and needs to be thawed. This issue can occur during the colder months as
      the pipe runs outside but can be resolved fairly easily without the need for an engineer
      as the pipe just needs to be thawed out. Find out everything you need to know by
      checking our handy guide to thawing a frozen condensate pipe.
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    • Zanussi

      Zanussi Boiler Error Codes

      Fault Code System Behaviour
      C0 Boiler chip card (BCC) activation fault
      C2 Boiler chip card (BCC) fault
      F1 Low water pressure
      F2 Flame loss
      F3 Fan fault
      F4 Flow thermistor
      F5 Return thermistor
      F6 Outside sensor failure
      F7 Low mains voltage
      F9 Un-configured printed circuit board (PCB)
      L1 Flow temperature overheat or no water flow
      L2 Flame loss
      L5 5 boiler resets in 15 minutes
      L6 False flame lockout
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    • Ideal

      Ideal Boiler Error Codes

      Fault Code System Behaviour
      C0 Boiler chip card (BCC) activation fault
      C2 Boiler chip card (BCC) fault
      F1 Low water pressure
      F2 Flame loss
      F3 Fan fault
      F4 Flow thermistor fault
      F5 Return thermistor fault
      F6 Outside sensor failure
      F7 Low mains voltage
      F9 Un-configured printed circuit board (PCB)
      L1 Flow temperature overheat or no water flow
      L2 Flame loss
      L5 5 boiler resets in 15 minutes
      L6 False flame lockout
      Fault Code System Behaviour
      0 The boiler is in standby mode awaiting either a central heating call or
      hot water demand
      C The boiler has a call for central heating but the appliance has reached the
      desired temperature set on the boiler
      D The boiler has a call for hot water but the appliance has reached the desired
      temperature set on the boiler
      C The boiler is operating in central heating mode
      d The boiler is operating in hot water mode
      F The boiler is operating in frost mode

      Ideal Logic Max System / Logic Plus System Boiler Error Codes

      Fault Description System Behaviour
      L1 Flow temperature overheat lockout or no water flow lockout
      L2 Ignition lockout
      LC Turn power off and on
      L6 False flame lockout
      F1 Low water pressure
      F2, FN or LN Flame loss
      F3 Fan fault
      L4 or F4 Control / no flow thermistor fault
      L5 or F5 Return thermistor fault
      F6 Outside sensor fault
      F7 Low mains voltage. Contact electricity provider.
      F9, L9, F8 or L8 Printed circuit board (PCB) un-configured or fault
      FU Diff greater than 50c check isolation valves are open
      No central heating
      No hot water
      No display

      Ideal Logic Max / Logic Plus Regular Boiler Error Codes

      Fault Description System Behaviour
      L1 Flow temperature overheat lockout or no water flow lockout
      L2 Ignition lockout
      LC 5 restarts within 15 minutes
      L6 False flame lockout
      FA Flow return reversed
      FD No water flow
      F2 or FN or LN Flame loss
      F3 Fan fault
      L4 or F4 Control / no flow thermistor fault
      L5 or F5 Return thermistor fault
      F6 Outside sensor fault
      F7 Low mains voltage Contact electricity provider
      F9, L9, F8 or L8 Printed circuit board (PCB) un-configured or fault
      FU Diff greater than 50c check isolation valves are open
      Ideal Logic Max Plus Combi Boiler Error Codes
      Fault Description System Behaviour
      Overheat lockout Bleed radiators, refill system to 1.0 bar, check that radiator and boiler valves are open and reset boiler. If fault continues book an engineer.
      Ignition lockout Check gas appliances work and restart boiler.
      Too many restarts 5 starts within 15 minutes. Turn power on and off.
      Flame on before gas on False flame lockout.
      Water pressure With boiler off and system cold fill system to 1.0 bar and bleed radiators if fault continues contact an installer.

      Ideal Vogue Boiler Error Codes

      Fault Description System Behaviour
      Too many resets 5 restarts within 15 minutes
      Flame on before gas valve on Flame on before gas valve is on
      Flow thermistor fault Flow thermistor error
      Low mains voltage Less than 185v to boiler then check voltage at boiler mains in if mains voltage is okay pump needs replacing
      Low water pressure Low water pressure
      Flow return reversed Check if the flow thermistor is correctly clipped to pipe. If not, replace flow thermistor.
      Printed circuit board
      (PCB) recently replaced
      Reset boiler
      Pump rotor blocked Unblock pump
      Flow temperature set point cannot
      be increased to 80c
      Check flow and return thermistors securely clamped to pipes check flow and return thermistor

      Ideal Boiler Error Descriptions

      Fault Description Cause
      Thermal fuse lockout Reset the boiler
      Too many boiler resets 5 resets within 15 minutes. Turn power off and on.
      Printed circuit board (PCB) replaced incorrectly Ensure the boiler chip card (BCC) is fitted correctly.
      Low mains voltage Less than 160V to boiler. Contact electricity provider.
      Low water pressure Increase system pressure to 1.5 bar
      Flow/Return reversed Check if flow thermistor is correctly clipped to pipe. Replace flow thermistor.
      Printed circuit board (PCB) replaced Reset the boiler
      No connection to primary printed circuit board (PCB) Unblock pump
      Pump rotor blocked No connection to primary printed circuit board (PCB)
      Flow temperature set point cannot be increased to 80ºC Ensure flow temperature is not limited within installer mode
      Pump runs during the night Ensure system frost protection temperature set point isn’t set too high
      Has the printed circuit board (PCB) just been replaced? Reset the boiler
      Are the boiler, central heating and hot water systems filled with water? Are all isolation valves and radiator valves open? Fill and vent the system and open all isolation valves, then reset the boiler
      Is the Flow/Return differential across the boiler in excess of 30c Check the flow and return thermistors
      Check that the pump is rotating freely. Replace the pump, then reset the boiler
      If the boiler is reset, does it ignite for a short time and then extinguish? Check the detection electrode and associated harness for continuity, visual condition and position. Check if the condensate pipe is blocked.
      Is the gas pressure available at the boiler > 18mBar Check gas supply and rectify fault
      Is 215Vdc available at the gas valve during ignition? Check wiring from gas valve to printed circuit board (PCB) and replace if necessary, otherwise replace the main PCB
      Unplug the gas valve – is the resistance between the pins between 1kW and 10kW? Replace gas valve
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    • Baxi

      Baxi Platinum Error Codes

      Fault Code Possible Cause
      E20 Central heating NTC error
      E28 Error with the NTC flue. Possible air pressure switch error. Blocked flue or condensate
      or wing fault
      E50 Hot water NTC error
      E110 Thermostat operated safety
      E119 Water pressure switch error – Not operated.
      E125 Primary circuit error circulation fault
      E130 FLue NTC Operation error
      E133 Gas supply Error or flame failure
      E160 Fan Error / Fan Wiring Error
      E193 Pre-circulation error
      Baxi EcoBlue Error Codes
      Fault Code Possible Cause
      110 Overheated – try bleeding your radiators
      117 Water pressure too high
      118 Water pressure too low
      125 Water circulation fault
      133 Safety time to establish flame exceeded
      E10 Outdoor sensor error
      E20 Central heating thermistor sensor fault
      E28 Flue thermistor fault
      E54 Domestic hot water (DHW) flow sensor fault
      E78 Water pressure sensor fault
      E100 Internal clock time error on printed circuit board (PCB)
      E109 Poor circulation
      110 Overheat – try bleeding your radiators
      111 Maximum limit of flow temperature
      117 Water pressure too high
      118 Water pressure too low
      119 System pressure too low
      125 Water circulation fault
      127 Legionella (cause of Legionnaires’ disease) protection temperature not reached
      128 Loss of flame during operation
      133 Safety time to establish flame exceeded
      153 Forced reset unit unlocked
      160 Fan fault
      162 Air pressure switch error
      164 Pressure Sensor Error (UK) – Heating flow switch error (Ireland)
      166 Air pressure switch fault
      270 Dry fire
      432 Earth connector error
      433 Heat exchanger temperature exceeded (greater than 95 degrees)

      EcoBlue Advance / Ecoblue Regular Gas Boiler Flashing Light Error Codes

      Fault Code Possible Cause
      1 green flash Boiler temperature reached. No action required.
      3 green flashes Temporary flame loss. Boiler will self reset, if fault continues you will see 3 red flashes.
      4 green flashes Communication error between printed circuit board (PCB) and control. Temporary error,
      will self reset.
      5 green flashes Parameter error on printed circuit board (PCB). Temporary error, will self reset
      6 green flashes Miscellaneous error. Temporary error, will self reset.
      1 red flash Sensor error, temperature fault or flow fault.
      2 red flashes Boiler overheat tripped
      3 red flashes Ignition fault. Boiler has attempted to light 5 times and failed.
      4 red flashes Fan fault
      5 red flashes Parameter storage unit (PSU) error.
      6 red flashes Miscellaneous error.

      Baxi Duo-tec/Megaflo Error Codes

      Fault Code Possible Cause
      E10 Outdoor sensor fault
      E20 Central heating thermistor sensor error
      E28 Flue thermistor error
      E110 Boiler overheat error
      E119 Low water pressure error
      E125 Primary water circulation error
      E131 Flue overheat lockout error
      E133 Ignition error
      E160 / E161 Fan error
      E164 Pressure sensor fault
      E167 Printed circuit board (PCB) error
      E168 Printed circuit board (PCB) lockout error
      E193 Circulation error

      Baxi 200 / 400 Combi Gas Boiler Error Codes

      Fault Code Possible Cause
      H.01 – .00 Loss of communication between gas valve and boiler board.
      Possible fault in air/gas unit or loose connection to gas valve.
      H.01 – .05 Difference between the flow and return temperature is too high,
      sensor error or insufficient circulation.
      H.01 – .08 Sensor fault, flow temperature increasing too fast in heating mode or insufficient circulation.
      H.01 – .14 Maximum flow temperature value exceeded or insufficient circulation – temporary fault.
      H.01 – .18 No water circulation, insufficient circulation or sensor error.
      H.01 – .21 Temporary error – flow temperature increasing too fast in domestic hot water (DHW) mode,
      insufficient circulation or sensor error.
      H.02 – .02 Temporary error – no input of parameters C1/C2. Printed circuit board (PCB) not configured.
      H.02 – .03 Temporary error- incorrect configuration settings C1/C2.
      H.02 – .04 Temporary error- parameter fault. Incorrect parameters.
      H.02 – .06 Temporary error caused by system water pressure, water leak on boiler, water leak on system.
      H.03 -.00 Temporary error with communication, negative temperature coefficient thermostat (NTC)
      or flue sensor. Sensor could also be unconnected or have a bad connection.
      H.03 – .01 Communication error with the printed circuit board (PCB)
      H.03 – .02 Flame error – no flame during operation.
      E.00 – .04 Return temperature sensor open-circuit. Sensor not or badly connected.
      E.00 – .05 Return temperature sensor short-circuit. Sensor not connected or badly connected.
      E.01 – .02 Temperature measured by return sensor greater than flow sensor.
      E.01 – .04 Loss of flame detected 5 times in 24 hours (with burner on).
      E.01 – .11 Incorrect fan speed – external draught over the boiler or defective gas/air unit.
      E.01 – .12 Requires reset – temperature measured by return sensor greater than flow temperature.
      E.01 – .17 Reset the boiler – no circulation, sensor fault either not connected or has a bad connection.
      E.01 – .20 Maximum flue gas temperature reached. No circulation or sensor fault.
      E.02 – .00 Reset button has been pressed.
      E.02 – .07 No or low system water pressure. system pressure less than 0.5bar
      E.02 – .16 Permanent fault caused by channel service unit (CSU) time-out or printed circuit board
      (PCB) damage.
      E.02 – .17 Loss of communication between gas valve and boiler printed circuit board (PCB)
      or fault in air/gas unit.
      E.02 – .19 Jumper 1 changed – check position of jumper 1.
      E.02 – .20 Jumper 2 changed – check position of jumper 2.
      E.02 – .21 Jumper 3 changed – check position of jumper 3.
      E.02 – .47 Wiring to external device error.
      E.02 – .48 Configuration to external device unsuccessful – check pairing to external device.
      E.04 – .00 Gas valve error – gas valve not detected.
      E.04 – .01 Flow temperature sensor short-circuited. Sensor not or badly connected, bad connection
      or sensor fault.
      E.04 – .02 Permanent fault. Flow temperature sensor open-circuited, sensor not or badly connected,
      bad connection or sensor fault.
      E.04 – .03 Permanent fault. Critical flow temperature reached, non-existent or insufficient circulation.
      E.04 – .04 Permanent fault. Flue temperature sensor short-circuited, sensor not or badly connected,
      bad connection or sensor fault.
      E.04 – .05 Permanent fault. Flue temperature sensor short-circuited, sensor not or badly connected,
      bad connection or sensor fault.
      E.04 – .06 Permanent fault. Critical flue gas temperature value reached, no circulation or sensor fault.
      E.04 – .08 Permanent fault. Maximum safe temperature value reached, safety thermostat open-circuited,
      no circulation, sensor not or badly connected, bad connection or sensor fault.
      E.04 – .10 Failure to light (could be gas supply issue).
      E.04 – .12 Permanent fault. False flame signal, short-term fluctuation of the mains, ionisation current
      present even though there is no flame, the burner remains very hot (CO2 too high) or defective
      gas/air unit.
      E.04 – .13 Permanent fault. Fan rotor blocked, fan seized or wiring to fan damaged.
      E.04 – .17 Permanent fault. Problem with gas valve or defective gas/air unit.
      Baxi 600 Combi Gas Boiler Error Codes
      Fault Code Possible Cause
      E09 Gas valve connection cable.
      E10 External probe fault.
      E12 Differential water flow switch fault (still open).
      E13 Differential water flow switch fault (still closed).
      E15 Gas valve command fault.
      E20 Central heating negative temperature coefficient (NTC) thermostat fault.
      E28 Flue negative temperature coefficient (NTC) thermostat fault.
      E40 Central heating return negative temperature coefficient (NTC) thermostat fault.
      E50 Domestic hot water (DHW) negative temperature coefficient (NTC) thermostat sensor fault
      (tank boiler) (s.c.) or DHW NTC sensor fault (tank boiler) (o.c.).
      E83/E84/E85/E86/E87 No communication.
      E109 Pre-circulation fault.
      E110 Boiler max temperature exceeded for gradient (probable pump jammed or air in the circuit
      Boiler max temperature exceeded for over temperature (probable pump jammed or air in the
      circuit Safety thermostat sensor tripped.
      E118 Primary system water pressure too low (< 0.5 bar).
      E125 Circulation fault (primary).
      E128 Frequent flame failure (12 times).
      E129 Safety error for frequently loss of flame with max correction during the ignition during
      Calibration Function.
      E130 Flue thermostat sensor tripped (lockout).
      E133 Failure to light (could be a gas supply issue).
      E134 Elapsed time gas valve open without gas
      (short request in a short period)
      E135 Interruption of gas supply (internal error).
      E154 Flow/return sensor temperature test.
      E160 Fan or fan wiring fault.
      E163 Domestic hot water (DHW) negative temperature coefficient (NTC) thermostat sensor fault (s.c.)
      or DHW NTC sensor fault (o.c.).
      E270 Circulation fault (dry fire).
      E317 Wrong power supply electrical frequency (Hz).
      E321 Hot water negative temperature coefficient (NTC) fault.
      E384 False flame.
      E385 Under voltage.
      E430 Water pressure temporary test.
      E430 + Flame ‘crossed’ Water pressure test failed.

      Baxi MainEco Error Codes

      Fault Code Possible Cause
      1 Green Flash Boiler temperature reached – no action required
      3 Green Flashes Temporary flame loss – this is a temporary error, the system should reset on its own
      4 Green Flashes Communication error between printed circuit board (PCB) and Control – this is a temporary
      error, the system should reset on its own
      5 Green Flashes Parameter error on parameter storage unit (PSU) or printed circuit board (PCB) – this is a
      temporary error, the system should reset on its own.
      6 Green Flashes Miscellaneous error
      1 Red Flash Sensor error, sensor fault, temperature fault or flow fault – this is a temporary error, the system
      should reset on it’s own.
      2 Red Flashes Boiler overheat tripped
      3 Red Flashes Ignition fault. Boiler has attempted to light 5 times and failed
      4 Red Flashes Fan Fault
      5 Red Flashes Parameter storage unit (PSU) error
      6 Red Flashes Miscellaneous

      Baxi Avanta Range Error Codes

      Fault Code Possible Cause
      E0 Temperature sensor fault
      E1 Overheated – try bleeding your radiators
      E2 Poor circulation – try bleeding your radiators
      E3 Printed circuit board (PCB) fault
      E4 Ignition failure – try bleeding your radiators
      E10 Poor/No circulation
      E12 Printed circuit board (PCB) Fault
      E13 Heat exchanger thermal fuse tripped
      E83 / 84 / 85 / 86 / 87 Fan fault normally E8
       

      Baxi GA Range Error Codes

      Fault Code Possible Cause
      E53 Poor combustion – flue terminal may be blocked
      E110 Overheated – try bleeding your radiators
      E117 System water pressure high – try bleeding water from your radiators
      E118 System water pressure low
      E125 Overheat – try bleeding your radiators
      E133 Gas supply fault
      E4 Ignition failure
      E09 Gas valve wiring fault
      E10 Outdoor sensor error
      E15 Gas valve connection fault
      E20 Central heating thermistor sensor fault
      E28 Flue thermistor fault
      E40 Central heating return thermistor fault
      E53 Flue obstruction
      E55 Calibration required
      E78 Water pressure sensor fault
      E92 Combustion test alarm during auto-setting
      E109 Poor circulation
      E110 Boiler overheat tripped
      E117 System pressure high (>2.9 Bar)
      E118 System pressure low(< 0.5bar)
      E125 Primary water circulation fault
      E128 Loss of flame during operation
      E129 Loss of flame during calibration
      E133 Ignition fault
      E135 Internal error
      E154 Primary flow fault
      E160 Fan fault
      E270 Dry fire
      E317 Wrong power supply (Hz)
      E321 Not water thermistor fault
      E384 Flame detected when gas valve off
      E385 Low voltage (less than 195v)
       

      Baxi Solo Error Codes

      Fault Code Possible Cause
      FLASH FLASH ON Fan error
      FLASH OFF FLASH Voltage less than 180V
      FLASH OFF ON Overheat lockout
      FLASH ON FLASH Printed circuit board (PCB) error
      FLASH ON ON Printed circuit board (PCB) fault
      OFF OFF OFF No power
      ON FLASH FLASH Circulation error or dry fire
      ON FLASH ON Thermistor error
      ON OFF FLASH Live and neutral reversed error
      ON OFF ON Ignition lockout error
      ON ON FLASH Printed circuit board (PCB) error
      ON ON ON Low voltage wiring harness error
       

      Error Code E133 and E28

      If you’re seeing either of these two error codes on your Baxi boiler, this is due to your condensate
      pipe being frozen. In the cold winter months this can happen easily as the condensate pipe runs
      outside. You can fix this issue by thawing out the pipe (if you feel confident to), find out everything
      you need to know about how to do it with our guide to thawing a frozen condensate pipe.
      g_content_rows-repeater_items_title
    • Ferroli
      Ferroli iBoiler Error Codes
      Fault Code System Behaviour
      A01 Ignition error – possible electrode fault or power too low, no gas or excessive condensate level
      A02 Electrode or card error
      A03 Heating sensor damaged, no water circulation or air in system
      F04 Wrong card parameter setting
      F05 Air pressure switch contact error – wrong flue baffle obstructed or not correctly sized
      A06 No flame after the ignition phase – low pressure in gas system burner minimum pressure setting
      F07 Air pressure switch error – contacts closed on activation of fan
      A09 Gas valve error – wiring could be disconnected or error with gas valve
      F10 Delivery sensor error, sensor damaged wiring shorted or disconnected
      F11 Domestic hot water (DHW) sensor error – sensor damaged, wiring shorted or disconnected
      A15 Fault F05 generated 5 times within the last 24 hours – possible error with the air pressure switch
      A16 Gas valve error – wiring disconnected or faulty gas valve
      A23 Card parameter error – possibly wrong card parameter setting
      A24 Card parameter error – possibly wrong card parameter setting
      F34 Supply voltage under 170V – electric mains error
      F35 Faulty mains frequency – electric mains error
      F37 Error with system water pressure, possible pressure too low or water pressure switch is damaged
      F43 Exchanger protection intervention – could be because no system water circulation or there’s air in
      the system
      F50 Controller DBM23B error – controller could have an internal error
      F51 Controller DBM23B error – controller could have an internal error

      Ferroli Modena HE System Error Codes

      Fault Code System Behaviour
      A01 No burner ignition – possible electrode error, defective gas valve or incorrect inlet gas pressure
      A02 Flame detected with the burner off – electrode defective main board defective
      A03 High limit protection – possible flow temperature sensor not active or incorrectly located,
      no system circulation
      A04 Flue gas fault – fault F07 happened 3 times in the last 24 hours
      A05 Fan error – tachometer signal interrupted for 1 hour or longer
      A06 No flame after the ignition phase – electrode error, flame unstable, incorrect valve gas offset or
      flue gas circuit obstructed
      A41 Flow sensor error – sensor disconnected
      A42 Flow sensor error – sensor damaged
      F07 High fume temperature – the exchanger probe detects an excessive temperature
      F10 Flow sensor error – sensor damaged, short circuited, sensor damaged or wiring broken
      F11 Return sensor error – t-sensor damaged, short circuited, sensor damaged or wiring broken
      F13 Exchanger probe error – t-sensor damaged, short circuited, sensor damaged or wiring broken
      F14 Flow sensor error – t-sensor damaged, short circuited, sensor damaged or wiring broken
      F15 Fan problem – tachometer signal interrupted fan connection or damaged debris in fan.
      You need to check and clean fan debris
      F34 Supply voltage under 170v – electric supply error
      F35 Irregular mains frequency – electric supply problem
      F37 Incorrect system water pressure error – possible sensor damaged or pressure too low
      F43 Exchanger protection activation – no system circulation air in system
      F52 Flow sensor – fault sensor damaged
      A61 Controller ABM03B error – controller has an internal error
      A62 No communication between controller and gas valve – controller not connected or valve damaged
      A63 / A64 / F66 Controller ABM03B error – controller internal error
      Ferroli Modena HE Combi Error Codes
      Fault Code System Behaviour
      A01 No burner ignition – possibly no gas, detection or ignition electrode fault, defective gas valve,
      incorrect inlet gas pressure
      A02 Flame detected with the burner off – possibly caused by ionisation, defective electrode or main
      board defective. Check the printed circuit board (PCB) or ionizing electrode wiring
      A03 High limit protection – flow temperature sensor not active, incorrectly located or no system
      circulation. Check the position of the flow sensor or check pump and radiator valves
      A04 Flue gas fault – could be because F07 happened 3 times in the last 24 hours – check the flue
      A05 Fan problem – tachometer signal interrupted for 1 hour or longer – check the wiring and the fan
      A06 No flame after ignition phase – possible causes: detection electrode fault, flame unstable, incorrect
      valve gas offset, flue gas circuit
      A41 Flow sensor disconnected – check the correct positioning and operation of the flow sensors
      A42 Flow sensor fault – sensor needs changing
      F07 High fume temperature – the exchanger probe detects an excessive temperature for over 2 minutes
      – check the exchanger.
      F10 Flow sensor fault – possible causes: sensor damaged, short circuited or wiring broken check the
      wiring
      F11 Return sensor fault – sensor wiring shorted or broken – check the wiring
      F12 Domestic hot water (DHW) sensor fault – sensor damaged, wiring shorted or wiring disconnected
      – check the wiring
      F13 Exchange probe fault – wiring shorted or wiring broken – check wiring
      F14 Fan problem – tachometer signal interrupted fan connection. Fan damaged or debris in fan –
      check the wiring, the fan and clean debris
      F15 Supply voltage under 170v – electric supply problem – the electrical system needs checking
      F34 Irregular mains frequency – possible electric supply problem – the electrical system needs
      checking
      F35 Incorrect system water pressure – possible cause is pressure too low or sensor damaged –
      the system may need filling or check the sensor
      F37 External probe fault sensor damaged or short circuited – check the wiring
      F39 Exchanger protection activation – possibly caused by no system circulation, air in the system or
      sensor damaged
      F43 Flow sensor fault – sensor damaged – sensor needs changing
      F52 Controller 041049G0 fault – controller internal error
      A61 No communication between controller and gas valve controller – could not be connected or valve
      damaged
      A62 Controller 041049G – internal error
      A63 / A64 / F66 Controller DBM12 fault

      Ferroli Discontinued Boiler Error Codes

      DOMIcondens HE 26 C
      OPTIMAX HE PLUS 31C boiler
      OPTIMAX HE PLUS 38C boiler
      Boilers Fault Code System Behaviour
      DOMIcondens HE 26 C / OPTIMAX HE PLUS 31C A01 No burner ignition
      OPTIMAX HE PLUS 38C A01 The burner fails to light
      DOMIcondens HE 26 C /
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      A02 Flame present signal with burner off, possible electrical fault
      DOMIcondens HE 26 C /
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      A03 Over temperature protection activation
      DOMIcondens HE 26 C / OPTIMAX HE PLUS 31C A04 Fume thermostat fault
      OPTIMAX HE PLUS 38C A04 Fume extraction duct safety device activation
      DOMIcondens HE 26 C / OPTIMAX HE PLUS 31C A05 Fan fault or fume pressure switch fault
      OPTIMAX HE PLUS 38C A05 Fan protection activated
      DOMIcondens HE 26 C /
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      A06 No flame after the ignition phase
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      F07 High fume temperature
      DOMIcondens HE 26 C F07 Card parameter
      DOMIcondens HE 26 C A09 Gas value fault
      DOMIcondens HE 26 C /
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      F10 Delivery sensor 1 fault
      DOMIcondens HE 26 C F11 DHW sensor fault
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      F11 Return sensor fault
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      F13 Fume sensor fault
      DOMIcondens HE 26 C /
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      F14 Delivery sensor 2 fault
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      F15 Fan fault
      DOMIcondens HE 26 C A16 Gas valve fault
      DOMIcondens HE 26 C F20 Combustion control fault
      DOMIcondens HE 26 C A21 Poor combustion fail
      DOMIcondens HE 26 C A23 Set nominal system water pressure not reached within
      4 minutes
      DOMIcondens HE 26 C A24 4 fillings within 24 hours
      DOMIcondens HE 26 C /
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      A34 Supply voltage under 170V / 180V
      DOMIcondens HE 26 C A35 Faulty mains frequency
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      A35 Mains frequency anomaly
      DOMIcondens HE 26 C /
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      A37 Incorrect system water pressure
      DOMIcondens HE 26 C /
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      A39 External probe fault
      DOMIcondens HE 26 C /
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      A41 Sensor positioning
      DOMIcondens HE 26 C /
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      F42 Heating sensor fault
      DOMIcondens HE 26 C A43 Exchange protection activation
      DOMIcondens HE 26 C A50 Gas valve fault
      DOMIcondens HE 26 C A51 Poor combustion fault
      OPTIMAX HE PLUS 31C boiler /
      OPTIMAX HE PLUS 38C
      A62 No communication between electronic controller and gas valve
      g_content_rows-repeater_items_title
    • Alpha

      Alpha Boiler Fault Codes

      Fault Code Fault Possible Cause
      1 Ignition failure Gas supply, pressure tubes, ignition electrode, flame sensor electrode, ignition
      generator, lead flame sensor, electrode lead, gas valve setting, gas valve printed
      circuit board (PCB)
      2 Overheat boiler lock out Pump or flow problem, blocked heat exchanger, air in heat exchanger,
      overheat thermostat, thermal fuse (if open circuit then replace primary heat
      exchanger)
      3 High flue thermostat temperature Blocked or restricted primary flow, heat exchanger air flow blocked, flue restriction,
      flue sensor fault
      4 Gas valve electrical connection fault Gas valve lead connection fault, faulty gas valve or faulty printed circuit board (PCB)
      5 Heating flow sensor fault Flow sensor wire connections, flow sensor faulty
      6 Domestic how water (DHW) sensor fault DHW sensor wiring connection or DHW sensor faulty
      8 Maximum number of resets Refer to fault history codes
      10 Primary system pressure low Check expansion vessel pressure (1 bar), leak in system, expansion relief valve
      operated or primary pressure switch
      12 Cylinder sensor fault (FlowSmart only) Cylinder sensor wiring connections or cylinder sensor faulty
      15 Internal wiring error Check internal wiring connections to printed circuit board (PCB), Combi boiler
      domestic hot water (DHW) sensor X4, System boiler link X14
      16 Fan fault Fan wiring connections, fan fault or printed circuit board (PCB) fault
      20 Flame sensing fault Check flame sensing electrode and lead printed circuit board (PCB) fault
      24 Control panel button fault Jammed control panel or printed circuit board (PCB) buttons
      25 Overheat lock out Air in heat exchanger, blocked or restricted primary flow, heat exchanger air flow
      blocked, flue restriction, flue sensor fault, pump fault, boiler or heating circuit valve
      closed
      27 Insufficient primary flow Blocked or restricted primary flow, air in heat exchanger, boiler or heating circuit
      valve closed, pump fault or primary flow sensor fault
      29 Flue sensor fault Sensor wiring connection or flue sensor faulty
      31 Loss of communication with external
      control (Alpha Climatic)
      Remote control or receiver connection wiring
      37 Low supply voltage Check mains power supply
      38 Loss of flame rectification Flame sensing electrode and lead, check flue gas recirculation, check the gas
      valve settings and check the fan speed settings
      43 Loss of flame rectification Check gas supply working, check flame sensing electrode and lead, check for flue
      gas recirculation, check the gas valve settings, check the fan speed settings
      44 Safety lock out Check external control (room thermostat) requests and rapid on/off hot tap requests
      46 External sensor intervention External sensor and cable damaged or wet, continuity of external sensor and
      circuit, check connection at X19 on printed circuit board (PCB) and sensor
      connecting block
      47 Reduced burner output Air in heat exchanger, restricted primary flow, heat exchanger air flow blocked,
      flue restriction, flue sensor fault or pump fault
      51 Climatic RF communication fault Batteries need replacing, distance between boiler and climatic control too great,
      interference object blocking signal (metallic)

      E-Tec, E-Tec Plus, Evoke Combi Boilers Error Codes

      Fault Code Fault Possible Cause
      60 Pump error (stuck or there is an electrical
      pump fault)
      Pump operation (may need to free the pump shaft), issue with pump wiring or
      pump replacement needed.
      61 Air in the pump (restricted central heating
      flow)
      Flow and Return valves may not be open, iIncorrect system pressure, system not
      purged properly or flow return valves are open.
      70 Return/flow sensor
      Exchange from possible wiring fault
      Issues with sensor wiring and connections.
      Issues with sensor resistance.
      75 / 76 Return/flow sensor fault from possible
      failure of one or both sensors
      Issues with sensor resistance.
      SR Service reminder Service reminder countdown has reached 0 (this will not stop boiler from working)
      – boiler needs servicing.

      Protec Plus Error Codes

      Fault Code Fault Possible Cause
      0A1 Ignition failure Issue with gas supply.
      Ignition electrode position and spark issues.
      0A2 Flame detection fault Flame sensing electrode connections.
      A short circuit to the electrode or wires.
      0A3 Overheat thermostat lock-out Flame sensing electrode connections.
      A short circuit to the electrode or wires.
      0A5 Fan speed fault Problem with flue /ventilation.
      Issue with air inlet manifold and pipe.
      Damage or fault with fan.
      Fan wire connections.
      0A7 High flue temperature fault Air in the primary heat exchanger.
      System restrictions causing overheating.
      Flue run may have restrictions or blockages.
      0A8 Flame circuit fault Incorrect gas supply.
      Ignition electrode position and spark.
      Issues with flame sensing electrode gap and connections.
      0A9 Gas valve electrical error Valve connection issues.
      Main PCB.
      Gas valve operation issues.
      Gas contamination.
      0A15 Flow and return sensor anomaly detected.
      (incorrect temperature value shown on
      sensor.)
      Poor or incorrect circulation.
      External circuit influences.
      Problem with resistances of flow and return sensors.
      0A16 Flow sensor temperature rise incorrect
      (time taken for flow temperature to rise is
      too long.)
      System circulation issues.
      System volume or flow is too high.
      Boiler output is insufficient for the system.
      0A17 Return sensor temperature rise incorrect
      (time taken for flow temperature to rise
      is too long.)
      System circulation issues.
      System volume or flow is too high.
      Boiler output is insufficient for the system.
      0A18 Flow and return sensor anomaly detected.
      Sudden temperature change detected on
      the flow or return sensor.
      System circulation issues.
      Problem with operation of zone valves.
      Resistances and function of flow and return sensors needs checking.
      0A21 Main PCB fault Electrical connections.
      Water ingress in connections.
      0A30 Flow sensor short circuit Flow sensor connections and wires need checking.
      Water ingress in connections.
      0A31 Flow sensor out of range.
      (sensor measures a temperature not in
      normal range.)
      Problem with flow sensor connections and damaged wires.
      Sensor resistance values wrong.
      0A37 – Pro Tec 50 Insufficient system flow (if the system flow
      is too low for a certain length of time
      boiler will switch off)
      Flow switch reading needs checking.
      Restrictions or shut valves in system.
      Pump function issues.
      System pressure issues.
      0A37 – Pro tec 70, 90, 115 Insufficient system pressure (if the system
      pressure is too low the boiler switches
      off.)
      System pressure needs to be 1 – 2 bar if its not the pressure needs refilling to the
      correct amount
      0A43 Return sensor short circuit Problem with return sensor connections and wires.
      Water ingress in connections
      0A44 Return sensor out of range.
      Sensor measures a temperature outside
      normal working range
      Return sensor connections and damaged wires.
      Return sensor resistance values need checking.
      0A80 Flow and return sensor connection fault
      (may occur after several minutes of boiler
      operation.)
      Wires are not connected to the correct sensors.
      0.00E+00 Flame sensing fault. Flame sensing electrode connections need checking.
      Short circuit to the electrode or wire.
      0.00E+00 Maximum number of resets reached.
      (Over 5 reset attempts have been reached
      within 15 minutes.)
      Investigate initial fault code displayed.
      Power supply needs to be turned Off/On to clear this code
      0.00E+00 Main PCB fault All electrical connections need to be checked.
      Water ingress in connections.
      0.00E+00 DHW sensor out of range (measures a
      temperature outside normal working
      range.)
      DHW sensor connections and damaged cables.
      Issues with DHW sensor resistance values
      0.00E+00 Low power supply voltage Electrical socket connection issues.
      Problem with external power supply.
      Possible power disruptions
      0.00E+00 Insufficient system pressure System needs checking for circulation and restrictions.
      System pressure and gauge needs checking.
      Pressure switch and connections need checking.
      0.00E+00 Flue sensor short circuit Flue sensor connections and wires need checking.
      Water ingress in connections
      0.00E+00 Flue sensor out of range (measures a
      temperature outside of normal working
      range)
      Flue sensor connections, wires and flue sensor resistance values need checking.
      0.00E+00 Flow and return sensor anomaly detected
      (the sensor shows an incorrect
      temperature value)
      Poor or incorrect circulation / external circuit influences resistance of flow return
      sensors need checking
      0.00E+00 Flow and return sensor anomaly detected
      (sensor shows incorrect temperature
      value)
      M to O Connections need checking
      Compatible software on PCB needs checking
      0.00E+00 Simple cascade communication error Wiring connections needs checking on all boilers.
      Configuration, parameter 38.
      FE94 Display PCB fault. Electrical connections to display board need checking.
      Water ingress in connections.
      Damage to buttons or LCD screen.
      FE95 External flow sensor out of range or short
      circuit/ External flow sensor measures a
      temperature outside of normal working
      range.
      External flow sensor connections and wires need checking for damage.
      External flow sensor resistance values need checking to make sure they are
      between 5 and 0
      FE96 External sensor fault External sensor connections and wires need checking.
      Water ingress in connections.
      Boiler parameter settings are incorrect.
      FE97 Boiler PCB configuration error
      (may occur if the main PCB or display
      PCB is changed.)
      All electrical connections.
      Incorrect parameter settings on PCB.
      Press ‘-‘ CH button until ‘AUTO’ appears, then press and
      hold ‘RESET’ button until ‘bu1’ appears

      Alpha Flashing Light Errors Codes

      Fault Code Fault Possible Cause
      No lights on Electricity fault Check your electricity supply
      Illuminated red A or B Burner has failed to light Rotate selector switch to the reset position (3) and the ignition sequence will restart
      after a delay of about 30 seconds
      Illuminated yellow B or C Burner is alight No action required
      Flashing red A or B Overheat thermostat has operated /
      Temperature sensor fault
      Rotate selector switch to the reset position (3) to reset
      Flashing yellow every 5
      seconds or illuminated green D
      Electrical supply to the boiler is on No Action Required
      Flashing yellow B or flashing
      Red A
      Temperature sensor fault
      Illuminated red A and flashing
      yellow B or Flashing red A and
      flashing red B
      Blocked flue or fan fault
      Flashing yellow or flashing
      Red A or Flashing (alternating)
      red A and flashing (alternating)
      yellow B
      System pressure is very low and
      re-pressurisation is required
      Illuminated red A and
      flashing yellow B
      Pump fault or restricted flow
      Flashing red A and Flashing
      red B and flashing yellow C
      Temperature sensor wiring or flow and
      return connections incorrect
      Flashing red A and flashing
      red B and flashing yellow C
      indicators
      Flue temperature too high
      (air in the heat exchanger, heat exchanger
      blocked

      Alpha E-Tec Regular Gas Boiler Error Codes

      Fault Code Fault Possible Cause
      1 Ignition failure Check the gas supply, pressure tubes, ignition electrode, flame sensor electrode,
      ignition generator or lead flame sensor, gas valve setting and PCB.
      2 Overheat boiler lockout Pump or flow problem. Caused by a blocked heat exchanger, air in heat exchanger,
      overheated thermostat, thermal fuse (if open circuit then replace primary heat
      exchanger).
      3 High flue thermostat temperature Blocked or restricted primary flow. Heat exchanger air flow blocked, flue restriction,
      flue sensor fault.
      4 Gas valve electrical connection fault Gas valve lead connection fault. Faulty gas valve or faulty PCB.
      5 Heating flow sensor fault Flow sensor wire connections. Flow sensor faulty.
      6 Internal wiring error Incorrect wiring configuration detected. Internal wiring connections to PCB
      need checking.
      7 Chimney sweep function is active Chimney sweep function is active. E07 is displayed on the climatic remote control.
      8 Maximum number of resets Refer to fault history codes (INFO menud9)
      12 Cylinder sensor fault (FlowSmart only) Cylinder sensor wiring connection – cylinder sensor faulty.
      16 Fan fault Check fan wiring connection, fan fault or PCB fault.
      20 Flame sensing fault Check flame sensing electrode and lead PCB for faults.
      23 Heating return sensor fault Incorrect return sensor resistance value – return sensor wire connections or
      sensor could be faulty.
      24 Control panel button fault Control panel button is stuck in the ‘on’ position – check for jammed control panel
      buttons or jammed PCB button.
      27 Insufficient primary flow Blocked or restricted primary flow. Air in heat exchanger, boiler or heating circuit
      valve closed, pump fault or primary flow sensor fault.
      29 Flue sensor fault Check sensor wiring connection – flue sensor faulty.
      31 Loss of communication with external
      control (Alpha Climatic)
      Remote control or receiver connection wiring.
      37 Low supply voltage Check mains power supply.
      38 Loss of flame rectification Check flame sensing electrode and lead and for flue gas recirculation. Check or
      adjust the gas valve settings. Check or adjust the fan speed settings.
      43 Loss of flame rectification Check gas supply/working pressure, flame sensing electrode and lead, check for
      flue gas recirculation, check/adjust the gas valve settings, check/adjust the fan
      speed settings.
      44 Safety lockout Check external control (room thermostat) requests. Rapid on/off hot tap requests.
      45 High-temperature difference The boiler is detecting an unexpected increase between the system flow and
      return sensors. Boiler output is limited for boiler protection and once restored the
      boiler resumes regular operation.
      46 Optional thermostat intervention No continuity of optional thermostat circuit – check the optional thermostat and
      cable are not damaged or wet.
      47 Reduced burner output Flue thermostat has sensed high flue gas temperature and reduced the burner
      output to prevent damage. If the temperature continues to rise the boiler will
      lockout and the E03 error code will be displayed. This could be due to air in the
      heat exchanger, restricted primary flow or heat exchanger air blocked.
      49 Return sensor high temperature
      intervention
      Return sensor has detected a high temperature on the exchanger return circuit.
      51 Climatic RF communication fault The error between the communication of the climatic transmitter and boiler
      receiver. Could mean the batteries need replacing or the distance between the
      boiler and climatic control is too great or a metal object is blocking the signal.
      70 Return flow sensor error Possible wiring faults sensor is incorrectly fitted or the system is blocked –
      check the sensor wiring and connections, also check sensor resistance and
      circulation.
      71 No primary temperature increase detected From ignition the boiler detects no temperature rise in the primary circuit –
      check system filling and venting, air locks preventing flow check, blocked flow or
      closed valves.
      g_content_rows-repeater_items_title
    • Ariston

      Ariston Error Codes

      Fault Code Boiler Model Possible Cause
      Central Heating Circuit
      101 All Boilers Overheat
      102 E-Combi Evo
      E-System Evo
      Clas He Evo (Combi and system)
      Pressure sensor error
      103 All Boilers Insufficient circulation
      104 All Boilers Insufficient circulation
      105 All Boilers Insufficient circulation
      106 All Boilers Insufficient circulation
      107 All Boilers Insufficient circulation
      108 All Combi Boilers Insufficient water (request filling)
      109 Clas net one / Clas one Combi
      Clas system one
      System pressure greater than 3 bar
      110 All Boilers Central heating Flow temperature probe circuit open / short circuit
      112 All Boilers Central heating return temperature probe circuit open / short circuit
      114 All Boilers External sensor circuit open / short circuit
      116 All Combi and System Boilers Floor thermostat contact open
      118 All Boilers Heating delivery probe problem
      1p1 All Boilers Insufficient circulation indication
      1p2 All Boilers Insufficient circulation indication
      1p3 All Boilers Insufficient circulation indication
      1p4 Clas Net one Combi
      Clas one Combi
      Clas System one
      Insufficient circulation indication
      D.H.W Circuit
      202 Clas HE evo
      Clas he evo system
      E-combi evo
      E-system evo
      2 bottom storage temperature probe open/short circuit
      204 Clas HE evo
      Clas he evo system
      E-combi evo
      E-system evo
      Solar collector temperature probe open/short circuit
      205 E-combi one
      E-System one
      Clas Net one Combi
      Clas one Combi
      Domestic hot water in probe open circuit
      207 Clas HE evo
      Clas he evo system
      E-combi evo
      E-system evo
      Solar collector overheating
      208 Clas HE evo
      Clas he evo system
      E-combi evo
      E-system evo
      Collector frost protection temperature
      Internal printed circuit board (PCB)
      301 All Boilers EEPROM error
      302 All Boilers Communication error
      303 All Boilers Main printed circuit board (PCB) error
      304 All Boilers Too many resets (> 5) in 15 minutes
      305 All Boilers Main printed circuit board (PCB) error
      306 All Boilers Main printed circuit board (PCB) error
      307 All Boilers Main printed circuit board (PCB) error
      3P9 E-combi one
      E-System one
      Clas Net one Combi
      Clas one Combi
      Clas System one
      Schedule service
      External printed circuit board (PCB)
      407 Clas HE evo
      Clas he evo system
      E-combi evo
      E-system evo
      7 Room sensor circuit open/short circuit
      Ignition and Detection
      501 All Boilers No flame detected
      502 All Boilers Flame detected with gas valve closed
      504 All Boilers Flame lift
      5P1 All Boilers 1st ignition failed
      5P2 All boilers 2nd ignition failed
      5P3 All Boilers Flame cut-of
      Air Inlet / Flue gas outlet
      604 CLAS HE R
      E-Combi Evo
      E-System EVO
      Clas HE evo Combi
      Clas HE evo System
      Insufficient fan speed
      610 All Boilers Thermofuse open
      612 Clas HE Evo Combi
      Clas He Evo System
      E-Combi Evo
      E-system Evo
      Clas net one combi
      Clas one combi
      Clas system one
      Fan speed has incorrect measurement
      Multi-zone Heating
      701 E-Combi Evo
      E-System EVO
      Clas HE evo combi
      Clas he evo system
      Zone 2 outgoing sensor defective
      702 E-Combi Evo
      E-System EVO
      Clas HE evo Combi
      Clas HE evo System
      Zone 2 return sensor defective
      703 E-Combi Evo
      E-System EVO
      Clas HE evo combi
      Clas he evo system
      Zone 3 outgoing sensor defective
      704 E-Combi Evo
      E-System EVO
      Clas HE evo Combi
      Clas HE evo System
      Zone 3 return sensor defective
      705 E-Combi Evo
      E-System EVO
      Clas HE evo combi
      Clas he evo system
      Hydraulic separation sensor defective
      706 E-Combi Evo
      E-System EVO
      Clas HE evo combi
      Clas he evo system
      Zone 2 overheating
      707 E-Combi Evo
      E-System EVO
      Clas HE evo Combi
      Clas HE evo System
      Zone 3 overheating

      Clas Net One, Clas One, E-Combi and E-System Error Codes

      Fault Code Possible Cause
      External printed circuit board (PCB)
      411 Room sensor circuit open or short circuit zone 1
      412 Room sensor circuit open or short circuit zone 2
      414 Room sensor circuit open or short circuit zone 3
      Multi-zone Heating
      701 Send sensor defective (Zone 1)
      702 Send sensor defective (Zone 2)
      703 Send sensor defective (Zone 3)
      711 Return sensor defective (zone 1)
      712 Return sensor defective (zone 2)
      713 Return sensor defective (zone 3)
      722 Overheating in zone 2
      723 Overheating in zone 3
      750 All heating zones locked
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    • ATAG

      ATAG Boiler Error Codes

      When your ATAG boiler has an error, you will see an error symbol. This symbol is normally accompanied by one of the codes in the tables below.
      Fault Code System Behaviour
      10 Outside sensor error
      20 Flow sensor error
      40 Return sensor error
      61 Bus communication error
      78 Water pressure out of range
      105 Venting program active when power turned on / interrupted (runs for 7 mins)
      110 Exceeded safety temperature
      111 Exceeded maximum pressure
      119 X2 link position 4 and 5 missing
      129 Fan doesn’t start
      133 No flame after 5 ignition attempts
      151 Fan error or control unit defective (speed control is not achieved)
      154 Return greater than flow – flow temperature increases too fast
      101 Overheat error
      102 Pressure sensor fault
      104 Flow check failed
      108 Pressure needs filling to < 0.5 bar
      1P4 Pressure needs filling to 0.5 – 0.8 bar
      109 Pressure > Pmax error
      110 Send probe damaged
      112 Return probe error – could be damaged
      114 Outdoor sensor error – could be damaged
      141 Central heating flow switch is open
      201 Domestic hot water (DHW) probe damaged
      203 Tank probe damaged
      303 Printed circuit board (PCB) error
      304 Too many resets have occurred
      501 No flame detected
      612 Fan fault – fan isn’t starting up

      IC & IS Combi Boiler Error Codes

      Fault Code System Behaviour
      50 Domestic hot water (DHW) sensor error
      117 Pressure greater than 3 bar or pump pressure increase is too high
      118 Pressure less than 1 bar or pump pressure increase too low (no pump detection).
      Other Fault Codes
      If you see a spanner symbol this could be one of two things; firstly it could mean your boiler
      is in service mode. Secondly it could be blocking, if the boiler is blocking the code is only
      temporary and will clear itself or will lock the boiler after several attempts if the error keeps
      on occurring.
      ATAG Error code 133
      If you are seeing the error code 133, your boilers flame is failing after 5 ignition
      attempts. This could be down to your condensate drain pipe freezing. A frozen
      condensate pipe is something that is often easily fixed, you can find out how in this
      guide to defrosting a condensate pipe.
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    • Biasi

      Biasi Boiler   Error Codes

      Fault Code Fault Image System Behaviour
      ER 01 + Reset N/A Lack of burner ignition on safety lockout
      ER 02 + Reset N/A Safety thermostat intervention lockout
      ER 03 + Reset N/A General lockout
      ER 04 + Faulty primary circuit (no water or absence of flow)
      ER 05 + Faulty fan control system
      ER 06 + Faulty c.h. temp. probe NTC
      ER 07 + Faulty d.h.w. temp. probe NTC
      ER 08 + Faulty external temp. probe NTC
      ER 09 + Faulty flue temp. probe NTC
      ER 10 + reset N/A Flue probe intervention lockout
      N/A Flame detection error (An flashing + number error flashing
      ER + 14 + Reset N/A Faulty pump or primary temperature above 105°C
      ER + 14 + Reset N/A Faulty pump or primary temperature above 105°C
      ER + 14 + Absence of flow from temperature gradient (>2K/s)/td>
      Li N/A Primary circuit temp. limit during d.h.w. operation
      N/A Boiler Stand-By, hyphens are turned on in sequence to simulate running /antifreeze protection activated)
      N/A Boiler Stand-By, hyphens are turned on in sequence to simulate running /antifreeze protection activated)
      N/A Filling request: The boiler works regularly and the display shows all the icons, but the signal FL is flashing every 1 sec.
      N/A Insufficient pressure: The boiler stops displaying the water lack error.
      30c N/A Boiler waiting for heat request
      N/A Boiler in summer mode (d.h.w.). The primary circuit temperature is displayed.
      N/A Boiler in winter mode (c.h.+ d.h.w.) The primary circuit temperature is displayed.
      N/A Boiler on demand for d.h.w. power. The d.h.w. temperature is displayed. / Boiler on demand for c.h. power.
      N/A Burner ignition (spark)
      N/A Flame present (Burner on)
      N/A Pre-heating function 3 stars DHW comfort. This information is not displayed. It will be possible to check its state in the
      section “INFO” value “cF” (the signal “cF” is alternated to the CH temperature value until the end of this function). You
      can enter the function pushing the buttons 12 and 13 together. The function is confirmed showing ON or OFF alternating
      for 5 sec. This function is always active at every hour (it’s not possible to set the time slots unless a remote control is
      connected).
      N/A Pre-heating function 3 stars DHW comfort. This information is not displayed. It will be possible to check its state in the
      section “INFO” value “cF” (the signal “cF” is alternated to the CH temperature value until the end of this function). You
      can enter the function pushing the buttons 12 and 13 together. The function is confirmed showing ON or OFF alternating
      for 5 sec. This function is always active at every hour (it’s not possible to set the time slots unless a remote control is
      connected).
      N/A Boiler in anti-freeze phase (bP flashing + temperature flashing)
      N/A Boiler in antifrost phase (AF flashing + temperature flashing)
      N/A Set c.h. (all other symbols are disabled)
      N/A Set d.h.w. (all other symbols are disabled)
      N/A Pump activated for the post-circulation phase (Po flashing + temperature flashing)
      N/A Delayed burner ignition for setting the system (uu flashing + temperature flashing)
      N/A Maintenance required The wrench symbol is flashing (without showing any error)
      LP N/A Boiler in chimney sweep in function. The activation of the chimney sweep occurs configuring the “parameter P09=01”
      and is visualised: LP= minimum dhw hP= minimum heating cP= maximum heating dP= maximum dhw. The transition
      occurs with keys 16 (increase) and 15 (decrease) dhw temperature. The writing on the display alternates.
      N/A Boiler in chimney sweep in function. The activation of the chimney sweep occurs configuring the “parameter P09=01”
      and is visualised: LP= minimum dhw hP= minimum heating cP= maximum heating dP= maximum dhw. The transition
      occurs with keys 16 (increase) and 15 (decrease) dhw temperature. The writing on the display alternates.
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    • Daikin

      D2CND Combi Gas Boiler Error Codes

      Fault Code Possible Cause
      10-64 Gas valve circuit error, try resetting boiler
      10-65 Gas valve current fault, try resetting the boiler
      11-64 Ignition error – possible fault with valve on the gas line due to it being open. Try resetting the
      boiler after the third unsuccessful ignition.
      11-65 Flame stabilisation error – wait for the boiler ignition trial
      11-66 Flame Signal loss in safety time – try to reset the boiler after 3rd unsuccessful ignition
      11-67 Flame loss during operation. This is a temporary error, wait for the boiler to re-ignite.
      12-64 Ion control deviation is too big – try resetting the boiler
      12-65 Ignition scott actuators error – try resetting the boiler
      12-66 Ion base value lower than the upper factory limit, try resetting the boiler
      12-67 Ion base value exceeds the upper factory limit – try resetting the boiler
      12-68 Ion base value differs from the previous value – try resetting the boiler
      12-69 Offset adaptation at limit
      13-64 / 13-65 Fan speed error – try resetting the boiler
      16-64 Flue temperature signals overheating, the flue gas discharge path needs checking. Try resetting
      the boiler
      1J-64 High limit thermostat signalising overheating. Check the valve of the radiators in the heating,
      check if the Combi boiler water pressure is low, if it is then the heating circuit needs filling with
      water
      80-01 Return temperature sensor error – reset the boiler
      81-01 Flow temperature sensor error – try resetting the boiler
      81-65 Domestic hot water (DHW) temperature sensor error. The boiler will continue in operation but
      solar sensor has an error .
      8A-46 Freeze protection – the boiler won’t operate if flow temperature sensor reads a value that is less
      than 1°c
      8H-65 Flow temperature steep rise – the radiator valves may not be open enough to circulate water
      E1-64 Flame detected before burner operation – try resetting the boiler
      E1-65 Internal SCOT system error. Perform reset if needed
      E1-66 Calibration condition error, wait for burner to restart
      E1-67 Missing calibration – try resetting the boiler
      E1-68 Ion base value is outside the factory limits or saved incorrectly – try resetting the boiler
      E1-69 / E1-70 Parameter CRC fault – try resetting the boiler
      E1-71 EK lockout failure – this is a permanent error
      E1-72 SCOT flame amplifier – reset the boiler
      E1-73 Printed circuit board (PCB) error – try resetting the boiler
      H9-01 Outside sensor fault – try resetting the boiler
      HC-01 Domestic hot water (DHW) temperature sensor error. The boiler will continue to operate but you
      need to contact a heating engineer
      HJ-08 High system pressure – the boiler needs to discharge water down to 0.8 bar
      HJ-09 Low system pressure – increase the system pressure to 0.8 bar
      HJ-10 Water pressure sensor fault
      J6-01 Flow temperature sensor overheating due to a blocking fault or a lockout error – the valves of
      the radiator heating circuit may have an issue or the water pressure is low and needs filling
      J6-20 Return temperature sensor overheating due to a blocking fault or a lockout error – try resetting
      the boiler
      J6-21 Return temperature is higher than flow temperature. Burner operates itself after a small amount
      of time but if the problem repeats you need to contact a heating engineer
      JJ-64 Supply voltage is below low limit
      U2-01 Supply voltage is above high limit, your boiler should continue to operate but you need to
      contact a heating engineer
      U4-65 OpenTherm room thermostat connection is defective – your boiler will continue to operation but
      the thermostat is out of operation
      U4-66 CAN-bus timeout
      U4-67 Remote reset supervision, switch off the power at the mains – if problem repeats contact a
      heating engineer
      UA-64 Blocking during boiler chip card (BBC) update
      UA-65 Printed circuit board (PCB) requires a boiler chip card (BCC) update
      UA-66 Boiler chip card ID (BCC-iD) of internal Electrically Erasable Programmable Read-Only Memory
      (EEPROM) is inconsistent
      UA-67 Boiler chip card (BCC) is missing
      Error Code HJ-08 If you are seeing the error code HJ-08 this could be due to a high system pressure. To resolve this
      issue you need to discharge the water down to 0.8 bar. As well as this, you should also bleed your
      radiators. To do this check out our handy guide to bleeding radiators.
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    • Firebird

      Firebird Boiler Error Codes

      Fault Possible Cause
      E1 Control thermistor fault
      E2 Flue thermistor fault
      E3 Flue thermistor fault
      E5 Burner fault (possibly burner lockout)
      Thermostat at a high limit (cuts off) Reset boiler
      Occasionally some things can go wrong, that’s why we’ve
      created our handy at-a-glance table of Firebird error codes and a
      guide to Common Firebird Problems and Repair.
      Should you need professional help with your broken boiler, then
      simply use one of our enquiry forms and we will connect you with the
      best heating engineers local to you.
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    • Grant
      Grant Boiler Error Codes
      Fault Code Cause of Problem
      No display 12V transformer failure
      PP1 Inlet (return) water temperature sensor failure
      PP1 Inlet (return) water temperature sensor failure
      PP2 Discharge gas sensor failure
      PP3 Coil temperature sensor failure
      PP4 Return gas sensor failure
      PP5 Ambient temperature sensor failure
      PP6 Discharge gas overheat protection
      PP7 Winter anti-freeze protection in operation
      EE1 High pressure – circulating pump failure or circuit air locked
      EE2 Low pressure
      EE3 Open circuit between PCB terminals 23-24
      EE4 Supply L and N are reversed
      EE8 Communication failure
      Flashing on and off Defrosting
      E01 Internal control fault
      sHr HP flow sensor short / HP return sensor short
      OPn HP flow sensor open / HP return sensor open
      SUP Supply sensor short / Supply sensor open
      OUTDR Outdoor sensor short / Outdoor sensor open
      C2849 Fault C; Chassis Code
      Problem is controller area network wiring bus and modules.
      fault two; MFG – Manufacturer Specific
      Fault eight; Ignition System Or Misfire
      fault four; BBV Sensor Circuit Low Voltage
      fault nine; Kick-Down Switch Failed Short
      U2453 Fault U: Network Code
      Problem is climate control system, lighting, airbags, etc..
      fault two; MFG – Manufacturer Specific
      fault four; Transmission
      fault five; TP Sensor Learn Not Complete
      fault three; Transmission Control Module Reprogrammable Memory

      Grant Boiler Error Description

      Grant Fault Fault Description
      Boiler Will Not Start Low pressure cut-out activated No electrical supply to burner Check
      controls are switched on and calling for heat Boiler thermostat and/or
      overheat thermostat faulty
      Burner lights but goes to lock-out Fault with burner No fuel supply Oil tank empty Fire valve closed Fire valve
      closed. Fuel line filter is blocked Oil supply line is air locked Excessive
      combustion air Fault with burner
      Burner fires but smoke visible from flue or high
      smoke number
      Insufficient combustion air supply to burner Incorrect or faulty nozzle fitted
      Fuel pressure too high
      Burner pulsates Insufficient combustion air supply to burner
      Burner cycles On and Off Contaminated combustion air (balanced flue) Insufficient oil flow to burner
      due to restriction in supply line Excessive combustion air
      Fumes and puffing on starting Flue is blocked Insufficient flue draught Flue pipe or liner is too large or
      existing stack is unlined Insufficient combustion air supply to burner
      Flame slow to stabilise on starting Insufficient combustion air supply to burner Fuel pressure too low
      Oil smells Oil leak in supply line or burner
      Combustion fume smells Leak around boiler cleaning door Burner not correctly fitted on mounting
      flange Burner seal ‘O’ ring damaged or missing. Leakage around flue
      connection
      Overheat thermostat operating Faulty boiler thermostat Thermostat sensor not connected to printed circuit
      board (PCB) – Vortex Combi only Faulty overheat thermostat
      No water flowing from hot tap Mains water supply is not connected to cold water inlet of boiler One or
      more isolating valves, stop cocks, etc. in the pipework are closed The cold
      water isolating valve in the boiler is closed There is a blockage
      (or blockages) in the pipework
      No hot water operation Hot tap is not connected to hot water outlet of boiler Insufficient flow of
      water through boiler Boiler cold water and hot water connections reversed
      Thermostatic mixing valve incorrectly fitted Pump is not operating in hot
      water mode Diverter valve microswitch(es) faulty Diverter valve
      microswitches not operated Diverter valve seized Diverter valve diaphragm
      failed
      Low water temperature at tap Flow of water through boiler too high Boiler thermostat incorrectly set
      Thermostatic mixing valve incorrectly set Faulty boiler thermostat Pump
      speed setting too low Pump is incorrectly fitted
      Hot water for short period only Burner not firing for hot water (after a short time) Burner oil pressure set
      too low at oil pump Incorrect oil nozzle fitted to burner
      No operation on heating Timeswitch either not set, or not in an ‘ON’ period Timeswitch not operating
      Faulty timeswitch Faulty timeswitch switch contacts Timeswitch OK but not
      switching boiler on Heating switch set to ‘HOT WATER ONLY’ Room
      thermostat not calling for heat Faulty room thermostat No room thermostat
      or external timeswitch connected to boiler
      Flow temperature low Boiler thermostat is set too low Boiler thermostat faulty Boiler is underfired
      Combustion setting of burner incorrect Boiler heat exchanger is sooted up
      Grant Vortex / Eco / Pro Boiler Error Codes
      Fault Code Cause of Problem
      No fuel supply Insure that an adequate supply of fuel is available and that the fuel supply
      valve is open – check the condition of the fuel filter and clean if necessary,
      ensure fuel supply is reaching burner and vent pump
      No Electricity Supply Ensure electricity supply to the boiler is switched on and that all controls
      are calling for heat – ensure that the overheat thermostat has not tripped,
      reset if necessary and check the mains supply
      Burner not starting – fuel and electricity supplies
      present
      Reset boiler on the burner control box – if it is lit refer to burner fault finding
      charts
      Burner lights but goes to lock out If the flame is unstable check the combustion setting
      Visible smoke from flue or high smoke number Insufficient air supply. Check the air damper setting and the condition of
      the fan check room ventilation, check the nozzle size and type, fuel pressure
      may be too high, check and adjust
      Burner pulses Insufficient air supply – check the air damper setting and the condition of
      the fan, check room ventilation
      Flame slow to stabilise during start up Insufficient air supply – Check the nozzle size and type as fuel pressure may
      be too low, check and adjust insufficient draught clean boiler heat
      exchanger and check condition of flue
      Water temperature low Undersize nozzle and or low fuel pressure check condition of boiler heat
      exchanger and clean if necessary. Check the boiler thermostat, check the
      combustion setting, check the condition of the fuel filter
      Boiler operating an overheat thermostat Faulty boiler thermostat – no circulation, check circulating pump, check for
      air lock
      Fumes and puffing during starting Check the condition of the chimney to ensure it is not blocked and is high
      enough to produce the required draught – check that there is an adequate
      air supply near the burner fan is not drawing products out of the burner
      Oil odours Check all fuel line connections and remake as necessary
      Combustion fumes smell Check boiler cleaning cover and seal are correctly fitted, check burner is
      correctly fitted onto flange, check flue is correctly sealed into flue outlet of
      boiler, check the condensate pipe and trap are operating correctly

      Grant Vortex Blue Error Codes

      Fault Code Cause of Problem
      Red blinking light Presence of a false flame signal before heat request
      Red blinking light Presence of false flame signal during pre-purging
      Red blinking light Presence of false flame signal during post-purging or pre-heating
      Red steady on UV sensor defective or dirty oil valve defective fault – ignition transformer
      badly regulated burner, oil fuel not present
      Red blinking light Badly adjusted burner, oil valve defective or dirty UV sensor defective or dirty
      Red and orange blinking inverted Error with oil valve internal control circuit that drives the oil valve error
      Red green blinking inverted Internal memory error
      Orange green blinking inverted Check presence of voltage, check the condition of the fuses, check that safety
      thermostat is not in lockout
      Off Eliminate the extraneous light
      Off Check that plugs and sockets are connected properly
      Red blinking light Eliminate the extraneous light
      Red steady on Clear it / replace it / check the pressure and output of the fuel / check air
      output change nozzle check the coil od solenoid valve
      Green blinking light Set the air according to the instructions of the manual or replace

      Grant Vortex Eco Error Codes

      Fault Code Cause of Problem
      Motor fails to run No electrical supply to boiler check on/off switch is on – it should be neon lit
      Lock-out light not lit Fuse has blown – check reason for failure
      Motor fails to run No power to burner motor
      Burner lock out Burner motor capacitor fault check and replace if necessary

      Grant Vortex Pro Combi Error Codes

      Fault Code Cause of Problem
      Power supply Check that fused spur for heating system and boiler is switched on – check
      that the electricity supply has not failed
      Heating system controls Check that the timer or programmer is working and set to an on period
      Boiler controls Check boiler on/off switch is set to on – check that power indicator on and
      control panel is lit
      Burner Check the burner lockout reset button is lit, if yes press the reset button to
      start the burner if burner fails call an engineer
      Heating system Check the heating system water pressure
      power If the boiler is not lit it could be a problem with power supply to the boiler
      switched off or possibly blown a fuse
      DHW pump If flashing this indicates either a store thermistor or PCB fault
      Flow If the boiler is not lit when a hot tap is opened this could mean there is a
      lack of water flow or possible flow switch problem
      Demand If not lit this indicates either timer or programmer is not calling for hot water /
      switch is not set to constant
      Burner If flashing this indicates a PCB fault
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    • Intergas

      Intergas Boiler Error Codes

      Fault Code System Behaviour
      10, 11, 12, 13, 14 Sensor fault S1
      20, 21, 22, 23, 24 Sensor fault S2
      0 Low system pressure
      0 Sensor fault after self check
      1 Temperature too high
      2 S1 and S2 interchanged
      4 No flame signal
      5 Poor flame signal
      6 Flame detection fault
      8 Incorrect fan speed
      27 Shortcut outside sensor temperature
      29, 30 Gas valve relay faulty
      Intergas Xtreme and Xclusive Boiler Error Codes
      Fault Code System Behaviour Possible solution / cause
      F000 Sensor defect Heat exchanger sensor needs replacing.
      F001 Temperature too high during central heating
      demand
      Air could be in system, central heating system needs bleeding. There could be an error
      with the pump & it could need replacing.
      F002 Temperature too high during domestic hot water
      (DHW) demand
      The wiring of DHW sensor needs checking, possible breakage.
      F003 Flue gas temperature too high Heat exchanger needs checking for contamination.
      F004 No flame during startup Gas valve is closed. Condensation drain is blocked and ignition needs checking.
      F005 Flame disappears during operation Condensation drain could be blocked, the air supply duct and flue needs checking for
      possible recirculation or blockage of flue gases.
      F006 Flame simulation error Gas valve could need replacing or burner controller could need replacing.
      F007 No or insufficient ionisation flow Wiring of ionisation/ignition pin could have a breakage shut down and could need
      replacing.
      F008 Fan speed incorrect Fan cable needs checking, fan or burner controller could need replacing.
      F009 Burner controller has internal fault Burner controller needs replacing.
      F010, F011 Sensor fault Possible issue with heat exchanger sensor, breakage or not connected properly.
      F012 Sensor 5 fault Wiring for flue gas sensor needs checking, possible breakage.
      F014 Mounting fault sensor Heat exchanger sensor is not mounted correctly and needs to be mounted properly.
      F015 Mounting fault sensor S1 Central heating flow sensor is not mounted correctly and needs mounting properly.
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    • Johnson and Starley
      Fault Image System Behaviour
      one black spotone black spot Ignition lockout
      Two black spotsTwo black spots High limit error
      Two spotsTwo spots No tacho from fan
      Three spotsThree spots High flue gas temperature
      Three spotsThree spots Flame circuit error
      Three spotsThree spots Valve drive circuit error
      Three spotsThree spots Dual sensor error
      Three spotsThree spots Default lockout
      Three spotsThree spots Remote reset lockout
      Three spotsThree spots ADC error
      Three spotsThree spots CRC error – SW switch
      Three spotsThree spots Flame signal lost 5 times in 4 minutes.
      Three spotsThree spots Boiler flow temp sensor open circuit
      Three spotsThree spots Domestic hot water (DHW) sensor short
      Three spotsThree spots Domestic hot water (DHW) sensor open
      Three spotsThree spots Low mains voltage
      Three spotsThree spots Water pressure error
      Three spotsThree spots OpenTherm sensor shorted to earth
      Three spotsThree spots Water pressure too high
      Three spotsThree spots No water pressure signal received from MMI
      Three spotsThree spots Boiler return temp. sensor open circuit
      Three spotsThree spots Flue gas temperature sensor short
      Three spotsThree spots Flue gas temperature sensor open circuit
      Three spotsThree spots Communication MMI – CVBC lost

      Johnson & Starley Boiler Error Codes

      Fault Code / Fault Image System Behaviour
      1 Flame lockout after several ignition attempts
      2 False flame
      3 High water temperature limit
      5 No tacho from fan
      8 Flame circuit error
      9 Valve driver circuit error
      11 Flow/return sensor calibration error
      12 Default lockout
      13 Elapsed the number of retrials
      21 ADC error
      26 Flame signal lost 5 times in 4 minutes
      31 Centra heating supply sensor error (open or short)
      44 Central heating return sensor error (open or short)
      7 High flue gas temperature
      25 CRC error
      30 Boiler flow temperature sensor short circuit
      31 Boiler flow temperature sensor open circuit
      32 Domestic hot water temperature sensor short circuit
      33 Domestic hot water temperature sensor open circuit
      34 Low mains supply voltage
      37 Low system water pressure
      40 High system water pressure
      41 No water pressure signal received from MMI
      45 Flue gas temperature sensor short circuit
      46 Flue gas temperature sensor open circuit
      47 Water pressure sensor open circuit
      99 Communication MMI -ESYS lost
      E01 Ignition lockout
      E02 False flame lockout
      E03 Overheat lockout
      E05 Fan fault
      E08 Flame circuit failure
      E09 Valve feed back error
      E12 EEPROM lockout
      E15 Sensor drift lockout
      E16, E17, E18 Sensor stuck lockout
      E21 ADC lockout
      E33 Return thermistor fault
      E34 Low power supply lockout
      E35 Flow thermistor fault
      F07 Exhaust sensor fault
      F13 Remote reset lockout
      F37 Low water pressure
      F40 Water pressure too high
      F47 Water pressure sensor not connected
      F52 Domestic hot water (DHW) sensor fault
      F53 Flue temperature sensor lockout
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    • Keston

      C36 Combi Gas Boiler Error Codes

      Fault Code Possible Cause
      E01 Ignition failure – the boiler has attempted to light 5 times and not succeeded – check the gas supply is on
      E02 False flame – possibly a problem with the power supply
      E03 Boiler overheat – check that any valves to the heating circuit have not been shut down, no air in the system and that
      the water pressure is correct
      E05 Fan failure – boiler cannot detect fan rotation – check fan operation and both connectors onto fan
      E07 Flue overheat – check combustion and flue temperature vs. return temperature – the flue temperature should be no
      more than 10C above return temperature. Possible heat exchanger fault.
      E08 Flame circuit error – possible control box fault
      E09 Valve drive error – possible gas valve or control box fault
      E10 Control box errors – possible faulty control box
      E11 The automatic test for calibration of flow and return sensors has failed – check both flow and return sensors are
      located on the correct pipes and are producing the correct readings
      E12 to E22 Control box errors – possible faulty control box
      E23 Water filling error – check water pressure sensor
      E24 Water pressure lost 4 times in 24 hours – possible leak, check system and boiler
      E25 Control box errors – possible faulty control box
      E26 Flame drop out – check for obstruction of the flue and/or air terminals, blockage/freezing of the drain pipe or a low
      gas supply (LPG).
      E30 Flow sensor short circuit – check connections to flow sensor
      E31 Flow sensor open circuit – check connections to flow sensor are in place
      E32 DHW sensor short circuit – check connections to domestic hot water (DHW) sensor
      E33 Domestic hot water (DHW) sensor short circuit – check connections to DHW sensor are in place
      E34 Mains supply voltage < 180V – may be a problem with your power supply
      E35 Mains supply frequency incorrect – may be a problem with the power supply
      E37 Water pressure error – increase the system water pressure
      E38 Reset key fault – replace fascia PCB
      E40 Water pressure too high
      E41 Communication error between fascia and control box – check cables
      E43 Return sensor short circuit – check connections to return sensor
      E44 Return sensor open circuit – check connections to return sensor are in place
      E45 Flue sensor short circuit – check connections to flue sensor
      E46 Communication error between fascia and control box – check cables
      E99 Flue sensor short circuit – check connections to flue sensor are in place
       

      S30 System Gas Boiler Error Codes

      Fault Code Possible Cause
      0 The boiler is in standby mode awaiting either a central heating call or hot water demand
      C The boiler has a call for central heating / hot water but the appliance has reached the desired temperature set on
      the boiler
      C And Burner Light The boiler is operating for central heating / hot water
      F And Burner Light The boiler is operating in frost mode
      F0 Boiler Chip Card (BCC) not fitted
      F6 Outside sensor failure
      F7 Low mains voltage
      F9 Printed circuit board (PCB) Fault
      L5 5 boiler resets in 15 minutes
      L6 False flame lockout
      C0 Boiler Chip Card (BCC) activation fault
      C2 Boiler Chip Card (BCC) fault
      F1 Low water pressure
      L1 Flow temperature overheat
      F2 Flame loss
      L2 Flame loss
      F3 Fan fault
      F4 Control / No flow thermistor
      F5 Return thermistor
       

      C40 C55 Combi Gas Boiler

      Fault Code Possible Cause
      Enn Fault causing a boiler shutdown
      E00 Flame detected when not expected – check boiler earth and probe condition
      E02 No ignition after restart – check gas supply, gas valve operation and ignitor electrode spark generation
      E03 Gas valve faulty or not connected
      E04 Power has been reset whilst boiler was in lockout
      E11 Internal electronics error – rest or replace control box
      E18 Flow overheat – check water circulation
      E19 Maximum return temperature exceeded – check circulation
      E25 Flow temperature increased too quickly – check water circulation
      E30 Difference between flow and return temperatures too high – check circulation.
      E31 Flow thermistor short circuit – check/replace connections/thermistor
      E32 Return thermistor short circuit – check/replace connections/thermistor
      E36 Flow thermistor open circuit – check/replace connections/thermistor
      E37 Return thermistor open circuit – check/replace connections/thermistor
      E44 Low water pressure
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    • Main
      Main Boiler Error Codes
      Fault Code System Behaviour
      E168 Error code E168 could mean that your boiler has detected a problem but can’t work out exactly what it is;
      E20 Central Heating NTC Fault indicate faulty components. You
      should make a note of the displayed error code
      E28 PCB Fault indicate faulty components
      E50 Hot Water NTC Fault indicate faulty components
      E110 Safety Thermostat operated – displayed when the primary water pressure is less than 0.5 bar. After
      repressurising the system the boiler should operate. Your installer will be able to advise you about the
      method of repressurising.
      E119 Water pressure switch not operated – displayed when the primary water pressure is less than 0.5 bar. After
      repressurising the system the boiler should operate. Your installer will be able to advise you about the
      method of repressurising
      E33 Interruption Of Gas Supply or Flame Failure indicates that the gas supply has been interrupted, ignition
      has failed or the flame has not been detected. Ensure that the gas supply has not been turned off, and turn
      the selector switch to the reset position and hold for at least 5 seconds. If the boiler does not relight, or the
      code is displayed regularly.
      E60 Fan or fan wiring fault
      Main Error Code E133 A Main boiler showing the error code E133 means that the condensate pipe has frozen. This is an issue that can happen
      during the cold winter months as the condensate pipe leads outside but luckily this is an issue that can be resolved fairly
      quickly without the need for an engineer. You just need to thaw out the condensate pipe, which you can find out how to do
      with our guide.
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    • Minstral
      Initial User Checks
      You are able to make some checks before calling out a service engineer.
      Check you have enough fuel: check the sight gauge.
      Check the fuel supply valves are open.
      Check the external fire valve hasn’t tripped: press the trip button.
      Is the boiler electrical supply on?
      Is the control panel high limit thermostat tripped? Check and reset if needed.
      Burner control box locked out: check and press the lens.
      Mistral Boiler Error Codes
      Fault Possible Cause
      Burner does not start Air locks, supply lines blocked or tank vent blocked (no fuel getting into tank)
      Restriction suspected / fuel supply fault Power supply to the boiler failed, burner control box locked out, burner motor fault or pump seized
      Burner fault locks out after 15 seconds Photocell fault, restricted oil supply, combustion setting out of specification
      No flame established (burner fault) Ignition failure, oil restricted or nozzle locked
      Burner fault runs but continually pulsates Condensate trap blocked or flue system blocked
      Lock-out Losing oil in the supply suction line or oil level in tank below minimum level
      Burner running but smokes Tank topped with wrong fuel/ Air supply restricted/ Dust build up
      Burner flame shuts down slowly Balanced flue system leaking/ Combustion leaks/ Suction line drawing air into fuel
      Burner fails to reach working temperature Burner output restricted/ Low efficiency/ Control thermostat fault
      Oil smells Oil leakage at connection
      No hot water Circulating pump seized/ Programmer channel off
      Flow and water temperature low Programmer for central heating or domestic hot water are off, debris build-up or low water supply pressure
      No central heating or hot water Programmer channels are off, thermostat fault or turned off
      Thermostat trips off Fault circulating pump
      No central heating Spring fault or return valve not moving or operating properly – room stat error
      No domestic hot water Spring fault, jammed in how water mode, flow switch blocked or faulty
      Discharges on pressure relief valve Pressure vessel has lost charge, insufficient expansion volume
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    • Potterton
      Promax Combi, System, and Store Error Codes
      Fault Code Possible Cause
      E10 Outdoor sensor error
      E20 Central heating thermistor sensor fault
      E28 Flue thermistor fault
      E50 Domestic hot water sensor fault
      E110 Boiler overheat tripped
      E119 System pressure too low
      E125 Primary water circulation fault
      E130 Flue thermostat sensor tripped (lockout)
      E131 Flue overheat lockout
      E133 Ignition fault
      E151 Printed circuit board (PCB) error
      E152 PCB error
      E160 Fan fault
      E161 Fan fault
      E164 Domestic hot water sensor error – could be a heating flow switch error)
      E167 Printed circuit board (PCB) fault
      E168 Printed circuit board (PCB) lockout
      E193 Circulation

      Potterton Promax Ultra, Gold/Titanium Combi & System Boiler Error Codes

      Fault Code Possible Cause
      E10 Outdoor sensor error
      E09 Gas valve wiring fault
      E10 Outdoor sensor error
      E15 Gas valve connection fault
      E20 Central heating thermistor sensor fault
      E28 Flue thermistor fault
      E40 Central heating return thermistor fault
      E50 Domestic hot water sensor fault
      E53 Flue obstruction
      E55 Calibration required
      E78 Water pressure sensor fault
      E83 / 84 / 85 / 86 / 87 No communication between room controller and boiler
      E92 Combustion test alarm during auto-setting
      E109 Poor circulation
      E110 Boiler overheat tripped
      E117 System pressure too high (>2.9 bar)
      E118 System pressure too low
      E125 Primary water circulation fault
      E128 Loss of flame during operation
      E129 Loss of flame during calibration
      E130 Flue thermostat sensor tripped (lockout)
      E133 Ignition fault
      E135 Internal error
      E154 Primary flow fault
      E160 Fan fault
      E270 Dry fire
      E317 Wrong power supply (HZ)
      E321 Hot water thermistor fault
      E384 Flame detected when gas valve off (false flame)
      E385 Low voltage (less than 195v)

      Potterton Assure Combi Boiler Error Codes

      Fault Code Possible Cause
      E09 Gas valve connection cable fault
      E10 External probe fault
      E12 Differential water flow switch is still open
      E13 Differential water flow switch is still closed
      E15 fault with the gas valve command
      E20 Central heating NTC fault
      E28 Flue NTC fault
      E40 Central heating return NTC fault
      E50 Domestic hot water (DHW) Negative Temperature Coefficient (NTC) sensor
      (tank boiler) (s.c) or DHW NTC sensor (tank boiler) (o.c.) fault
      E83 / E84 / E85 / E86 / E87 Communication error
      E109 Pre-circulation fault
      E110 Boiler max temperature exceeded for gradient (or over temperature)
      – Probably a jammed pump, air in the circuit or safety thermostat sensor
      tripped
      E118 Primary system water pressure too low
      E125 Primary circulation fault
      E128 Flame failure (12 times)
      E129 Frequent loss of flame (safety error )
      E130 Flue thermostat sensor tripped and locked out
      E133 Possible gas supply issue (failure to light).
      E134 Elapsed time gas valve open without gas
      E135 Internal error (interruption of gas supply)
      E154 Flow/return sensor temperature test
      E160 Problem with fan (possible wiring fault)
      E163 Domestic hot water (DHW) Negative thermistor coefficient (NTC) sensor
      (s.c.) or (o.c.) fault
      E270 Dry fire
      E317 Wrong power supply (HZ)
      E321 Hot water fault
      E384 False flame
      E385 Under voltage
      E430 Water pressure test
      E430 + Flame crossed Water pressure test failed
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    • Ravenheat

      Ravenheat Boiler Error Codes

      Fault Code System Behaviour
      F73 Heating circuit pressure sensor fault
      F74 Heating circuit pressure sensor fault
      F76 Thermal fuse fault
      F77 Fault in gas valve motor
      F83 No water in the installation – the temperature does not increase when the burner is lit
      F84 Permanent temperature difference betweenF flow and return heating sensors
      F85 Flow and return heating sensors fault
      F86 Underfloor heating contact fault
      ERR User interface fault
      4 Domestic hot water (DHW) sensor faulty
       

      Ravenheat CSI 120 Boiler Error Codes

      Fault Code System Behaviour
      17 Possible issue with fan voltage
      1 Boiler failed to ignite – problem with gas valve operation, fan failing to start, ignition control board
      and cables
      28 Failed low water – pressure switch or pump, possible issue with pump, incorrect system pressure
      or the low water switch pressure needs replacing
      12 Failed heating sensor – issue with heating sensor and could need replacing
      4 Failed overheat – the overheat thermostat needs checking
      30 Failed flue temperature – check operating system
      31 Failed flue temperature – the flue sensor needs checking or replacing
      2 Failed temperature – try resetting the boiler
       

      Ravenheat CS 80/90, WH System, WH 80/90 Boiler Error Codes

      Fault Code System Behaviour
      E02 Problem with the pump circulation
      E03 Flow sensor damaged
      E04 Domestic hot water (DHW) sensor damaged
      E05 Problem with fan – possibly no signal
      E06 Central heating (CH) sensor is overheating
      E08 Low water pressure
      E09 Overheat sensor overheating
      E10 High water pressure
      E13 Software error
      E21 Central heating (CH) return sensor overheating
      E22 Flue sensor overheating
      E23 Flue sensor damaged
      E24 Central heating return sensor error – possibly damaged
      E25 Main heat exchanger frozen
      E29 Domestic hot water (DHW) sensor overheating error
      E31 OpenTherm communication error
      E41 Different flow/return temperatures
      E42 Different temperature error
      E43 Different temperature error
      E44 Different temperature error
      E46 Water pressure sensor error – could be open or short
       

      Ravenheat HE 80/90 HE 25-30s, HE 80-98s, HE 8-98s or HE 25-30s compact

      Different temperature error
      Fault Code System Behaviour
      02E Problem with the pump circulation
      03E Flow sensor damaged
      04E Domestic hot water (DHW) sensor damaged
      05E Problem with fan, possibly no signal
      06E Central heating sensor is overheating
      08E Low water pressure
      09E Overheat sensor overheating
      10E High water pressure error
      13E Software error
      21E Central heating return sensor overheating
      22E Flue sensor overheating
      23E Flue sensor damaged
      24E Central heating return sensor error, possibly damaged
      25E Main heat exchanger frozen
      29E D.H/W sensor overheating error
      31E OpenTherm (OT) communication error
      41E Different temperature between flow and return
      42E Different temperature error
      43E
      44E Different temperature error
      46E Water pressure sensor error, could be open or short
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    • Viessmann

      Vitodens 200 Boiler Error Codes

      Fault Code System Behaviour Cause of Problem
      2 Burner control switches to lockout Safety chain was activated
      04, 05, 06, 08 Burner control switches to lockout Fan speed too high/low at start
      07, 09 Burner control switches to lockout Basic level of air pressure threshold in standby mode not correct
      0A Burner control switches to lockout Fault with fan speed
      0D Burner control switches to lockout Reset button pressed repeatedly or while burner is running
      1A, 1B Burner blocked Flow sensor 1, 2 faulty
      1F Burner blocked Differential flow rate too large
      25 Boiler operates with high boiler water
      temperature
      Emissions test switch turned to “hand symbol” for 30 minutes already
      26 Boiler operates with continuous relay test Setting mode for maximum or minimum rated input active for 30 minutes already
      35 Boiler does not activate Reset button (pressed while burner is OFF) with emissions test switch turned to “hand symbol”
      A2 N/A KM-BUS fault to Vitocom
      A5 N/A Short circuit / open circuit
      Fault Code 0B
      Boiler Model System Behaviour Cause of Problem
      Vitodens 200 Burner control switches to lockout, fan doesn’t idle after auto reset (incorrect fan rpm). Severe wind conditions in vent system
      Vitodens 100-W Burner blocked Insufficient water flow, incorrect flow direction or defective flow switch.
      Fault Code 0C
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 100-W Burner blocked Insufficient power supply
      Vitodens 200 Burner control switches to lockout Flame signal still present after switching off
      Fault Code 0F
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 222-F Control mode Displayed in the fault history
      Vitotronic 300 / Vitotronic 300-K,
      with Vitotronic 300 / Vitodens 200-W /
      Vitocontrol-S, with Vitotronic 100
      Control mode / Controlled operation Boiler service required
      Vitotronic 200 / 300 Normal operation Boiler service required
      Vitocontrol-S, MW1 with Vitotronic 100
      / Vitotronic 300-K,
      MW1S with Vitotronic 100
      Control mode Maintenance
      Fault Code 10
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 200-W / 222-F /
      Vitotronic 300 / 200/ 200-H / 050/200-H
      / 300-K / vitocontrol-S
      Boiler operates based on outdoor
      temperature of 32°F / 0°C
      Short circuit – Outdoor temperature sensor
      Vitotronic 300-K,
      MW2S with Vitotronic 100 /
      Vitodens 100-W (combiPLUS) / 200-w /
      Vitocontrol-S, WB2B with Vitotronic 100
      Controls as if the outdoor temperature
      / Constant Mode
      Outdoor temperature sensor shorted out
      Viessmann Fault Code 10, 14, F3, and F4
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 200 Burner control switches to lockout No flame signal is present
      Fault Code 18 and D1
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 100 / 200-W / 222-F / Vitotronic 300-K With 100
      / Vitocontrol-S
      Boiler operates based on outdoor temperature of 32°F
      / 0°C / Constant Mode
      Outdoor temperature sensor cable broken
      Vitotronic / 100 / 200 / 300 / 050/200-H /300-K /
      Vitocontrol-S, MW1 with Vitotronic 100
      Operates on basis of 32°F / 0°C outdoor temperature Open circuit – Outdoor temperature sensor
      Vitotronic 200-H / Vitotronic 300-K, MW1B with
      Vitotronic 300 / Vitotronic 300-K, MW2B with
      Vitotronic 200
      Controls as if the outdoor temperature Lead break, Outdoor temperature sensor
      Vitotronic 050/200-H Activates after 0°C / 32°F outdoor temperature Cable break – Outdoor temperature sensor
      Vitodens 100-W Burner in fault mode DIP switch S2 is set to “ON”
      Fault Code 19
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitotronic 300 Activates after 0°C / 32°F outdoor temperature Communication fault, Wireless Outdoor temperature sensor
      Fault Code 20
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocontrol-S with Vitotronic 100 / Vitotronic 300
      / 300-K / 200 / 100
      Stand-alone control unit without supply temperature
      sensor (possibly supply temperature not high enough)
      short circuit – Common supply temperature sensor
      Vitocontrol-S with Vitotronic 100 / Vitotronic 300-K,
      with Vitotronic 200
      Vitocontrol-S, controls in a stand-alone manner w/o supply
      temperature sensor (supply temperature may not be
      high enough)
      Common supply temperature sensor shorted out
      Vitocrossal 300 Regulates without supply temperature sensor
      (low-loss header)
      Short circuit – System Flow temperature sensor
      Vitodens 200-W / 222-F Regulates without supply temperature sensor
      (low-loss header)
      Short circuit – System supply temperature sensor
      Vitotronic 050/200-H< / 200 / 200-H / 300 Mixing valve closes/ closed Short circuit – Supply temperature sensor / mixing valve circuit M1
      Vitotronic 300-K, with Vitotronic 100 Vitotronic 300-K, MW1S controls in a stand-alone
      manner w/o strap-on sensor (supply temperature may not
      be high enough)
      Short circuit – Strap-on temperature sensor
      Vitodens 200-W Regulates without supply temperature sensor
      (low-loss header)
      System supply temperature sensor shorted out
      Fault Code 21
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitotronic 200 / 300 operation without influence of return water temperature Short circuit – Return water temperature sensor
      Viessmann Fault Code 28
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocontrol-S with Vitotronic 100 Vitocontrol-S, VD2/CT3/CM2 controls in a stand-alone
      manner w/o supply temperature sensor (supply
      temperature may not be high enough)
      Open circuit – Common supply temperature sensor
      Vitocontrol-S with Vitotronic 100 /
      Vitotronic 300-K,with Vitotronic 100
      Vitocontrol-S, WB2B controls in a stand-alone manner
      w/o supply temperature sensor (supply temperature may
      not be high enough)
      Common supply temperature sensor cable broken
      Vitocrossal 300 / Vitodens 200-W / 22-F Regulates without supply temperature sensor
      (low-loss header)
      System supply temperature sensor cable broken
      Vitotronic 050/200-H Mixing valve closes Cable break – Supply temperature sensor
      Vitotronic 050/200-H Mixing valve is closed Open circuit – Supply temperature sensor of mixing valve circuit M1
      Vitotronic 200-H / Vitotronic 200 / 300 Mixing valve is being closed Lead break, Supply temperature sensor, heating circuit with mixing valve M1 (heating circuit 1)
      Vitotronic 300 Vitotronic / 300-K with Vitotronic 300 / 200 Stand-alone control unit without supply temperature
      sensor (possibly supply temperature not high enough)
      Lead break, Common supply temperature sensor
      Vitotronic 300-K with Vitotronic 100 Vitotronic 300-K, MW1S controls in a stand-alone
      manner w/o strap-on sensor (supply temperature may not
      be high enough)
      Open circuit – Strap-on temperature sensor

      Fault Code 29, 41, 49, F80, F81, F83, F88 and F89

      Fault Code 30
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitotronic 200 / 300 Normal operation without influence of return
      water temperature
      Open circuit 1 or 2 – Return water temperature sensor (of mixing valve circuit 1)
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocontrol-S, with Vitotronic 100 / Vitocrossal 300 /
      Vitodens 200-W / 222-F / Vitotronic 100 / 200 / 300
      Burner is started and stopped via an adjustable high limit Short circuit – Boiler water temperature sensor
      Vitocontrol-S with Vitotronic 100 / Vitodens 100-W
      (CombiPLUS)/ 200-1
      Burner blocked Boiler water temperature sensor shorted out
      Fault Code 38
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens – 200-W, 222-F and COMBIPLUS Burner blocked Boiler water temperature sensor cable broken
      – Vitotronic 100, 200 and 300
      – Vitocontrol-S with Vitotronic 100
      Burner is switched on and off by the adjustable high limit Open circuit – Boiler temperature sensor
      Vitotronic 300-K with Vitotronic 300 / Vitotronic 300-K
      with Vitotronic 300
      The burner is started and stopped via a temperature
      controller
      Lead break, Boiler water temperature sensor
      Vitodens 100-W Burner blocked Boiler water temperature sensor lead broken
      Fault Code 40 And 44
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Mixing valve closes Heating circuit 2 with mixing valve supply short circuit on temperature sensor
      Fault Code 41
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitotronic 300 Operation without accounting for return water temperature Short circuit – Return water temperature sensor of mixing valve circuit 2
      Fault Code 48 and 4C
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Mixing valve closes / Closed Heating circuit 2 with mixing valve supply temperature sensor cable broken / open circuit
      Fault Code 50, 51, 58 and 59
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 200-W and 222-F No domestic hot water (DHW) – fault with DHW Short circuit/open circuit, DHW tank temperature sensor or lead break
      Fault Code 52
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitotronic 300 Control mode Short circuit – supply temperature sensor low-loss header
      Vitodens 100-W CombiPLUS Burner blocked (with CombiPLUS only) Flow sensor shorted out (in CombiPLUS)
      Fault Code 55, 56 and 57
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitotronic 300-K with Vitotronic 200 Control mode Maintenance or error on Vitotronic 100 of boiler 5-8
      Fault Code 5A, B7, and B8
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Control mode Lead break, low-loss header Supply temperature sensor
      All Viessmann boilers Burner blocked / control mode sensor cable broken
      Fault Code 5C, 5D, 5E and 5F
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitotronic 300-K with Vitotronic 200 Control mode Communication fault, Vitotronic 100 of boiler 5-8
      Fault Code 60, 68, 70, 78, BD, BE and BF
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers – No output reduction
      – Return control Open
      – Boiler with maximum temperature
      Short/open circuit – Temperature sensor [17A]
      Fault Code 80, 81, 82, 83 and FD
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Burner control unit in a fault state; system cools down;
      burner control unit locked out
      Short circuit – Boiler water temperature sensor, burner control unit
      Fault Code 88, 89, and E6
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitotronic 300 Burner control unit in a fault state Lead break, Boiler water temperature sensor, burner control unit
      Fault Code 8C, 8D, 8E and 8F
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocontrol-S with Vitotronic 100
      – Vitotronic 300-K with Vitotronic 100 / 200
      Control mode Communication fault, Vitotronic 100 of boiler 1-4
      Fault Code 90, 91, 92, 93, 94, 98, 99, 9A, 9B , 9C, 9E, 9F and AB
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Control mode Short circuit – Temperature sensor [5] / [6] / [7] / [10]
      Fault Code A0, A1, A2, AA, and AC
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitotronic 300
      – Vitotronic 300-K with Vitotronic 300
      Boiler cools down Fault, safety equipment at “X2 / X3 / X7” of plug-in adaptor 2 for external safety equipment
      Vitodens 200 – Boiler operates in emergency mode (after approx. 30 min)
      BUS fault
      – Boiler cools down
      -Internal BUS fault
      – Open circuit – Internal BUS connection
      Fault Code A3, B0, F1, FE1 and FE2
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Burner blocked Flue gas temperature sensor not properly positioned – check Sensor
      Fault Code A4
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 200 Pump runs at maximum speed Open circuit – BUS connection with variable speed heating circuit pump
      Fault Code A7
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocrossal 300
      – Vitodens 200-W, 222-F, 300
      Control mode (stays in factory default setting) Faulty Programming unit
      Fault Code A8
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 222-F Burner blocked. The venting program is started
      automatically
      Air lock in the Internal circulation pump or minimum flow rate not achieved
      Fault Code A9, BA, BB, BC and FE0
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Control Mode Communication error
      Fault Code AD
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocontrol-S with Vitotronic 100
      -Vitotronic 100
      -Vitotronic 300-K with Vitotronic 300
      Control mode Isolation valve configuration error: Coding OC:2, OC:3 or OC:4 set, and coding 4E:1 not set
      Fault Code B1
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Control mode Communication error – programming unit
      Fault Code B2
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 200 Boiler cools down Sensor inputs are not read correctly
      Fault Code B3 and E5
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 200 Setting via service level not possible Data points are not stored – internal fault VR20
      Fault Code B4
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocontrol-S with Vitotronic 100
      – Vitotronic 100, 200 and 300
      – Vitotronic 300-K with Vitotronic 100
      Emissions test mode Internal electronics fault
      Vitocontrol-S with Vitotronic 100 / Vitodens 200-W Regulates as if the outside temperature was 32°F (0°C) Internal fault
      Vitotronic 050/200-H Undefined control characteristics Internal electronics fault
      Fault Code B5
      System Behaviour
      Cause of Problem
      All Viessmann boilers Control mode Internal electronics fault
      Fault Code B6
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Constant mode Invalid hardware recognised
      Fault Code B9, ED, F0, FE5, FEC, FED, FEE, FEF, FFD and FFF
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Normal operation / fault around burner control unit Internal fault
      Fault Code C1
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Control Mode External safety equipment
      Fault Code C2-C8, CD-CF, D2-D8, DA-DF, and E0
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Control mode Open circuit – KM BUS to solar control unit / Extension AM1 / DE1-DE3 M1 /
      communication fault
      Fault Code C9, CA and CB
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocontrol-S with Vitotronic 100 / Vitotronic 100
      / 300 / Vitotronic 300-K with Vitotronic 300
      Boiler cools down Error: Maximum pressure limiter 1 2
      Fault Code CC and F0
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 200 Burner control unit switches to lockout
      (due to large line voltage fluctuations)
      Differential air pressure sensor / open circuit
      Fault Code D4
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Boiler cools down Fixed high limit has responded or fuse F2 has blown.
      Fault Code D5
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Boiler drives up to electronic maximum limit Boiler does not log in at the cascade control unit
      Fault Code E1, E7, E8, E9, EA, EB, EC and FF2
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Burner in fault mode Ionization current too high during calibration
      Fault Code E2 and E3
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 200-W / 222-F / Vitotronic 300 Burner in fault mode Heating water flow rate too low during calibration; flow switch caused shutdown
      Fault Code E4
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Burner blocked Fault, supply voltage 24V
      Fault Code EE and EF
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocontrol-S with Vitotronic 100 / Vitocrossal 300 /
      Vitodens 200-W / 222-F / Vitotronic 300
      Burner in fault mode At burner start, flame signal is missing or too weak
      Fault Code F5
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitodens 100-W / 200 / 300 / Vitotronic 300 Burner blocked Faulty Air pressure switch
      Fault Code F6, 58, F9, FE1, FE2 and FF6
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Gas pressure switch shows no gas pressure / Electrical
      connection fault
      Gas shut-off valve closed; gas pressure switch faulty; multiple problems with gas supply
      Fault Code FA and FB
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Burner in fault mode / Emergency operation Fan not at standstill / plug-in connection

      Fault Code FB7, FF4, FF2, FF7, FF8 and FF9

      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocrossal 200 Case A: Burner control unit in a fault state; system cools
      down; burner control unit locked out.
      Case B: Type of coding card
      Case A: Coding card not inserted in the burner control unit; incorrect or faulty coding card.
      Case B: Coding card does not match burner control unit.
      Fault Code FC
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Burner in fault mode Gas valve faulty, issue with modulation valve control or vent system blocked
      Fault Code FE
      Boiler Model
      System Behaviour
      Cause of Problem
      All Viessmann boilers Burner blocked or in fault mode Strong interference (EMC) field nearby, or faulty main printed circuit board (PCB)
      Fault Code FE4
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocrossal 200 Burner shuts down Multiple detection of undervoltage
      Fault Code FFA, FFB and FR
      Boiler Model
      System Behaviour
      Cause of Problem
      Vitocrossal 200 / 400-620 / 186-311 Fan runs without demand; burner control unit in a
      fault state
      Fan has not stopped, cable [100A] faulty, fan faulty, burner control unit faulty
      Viessmann Error Code F4 EE
      Viessmann error code F4 EE means that the condensate pipe has frozen and needs to be thawed.
      You can thaw out the pipe yourself fairly quickly and easily without the need for an engineer
      (if you feel confident enough), find out how with our guide to thawing out a frozen condensate pipe.
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    • Vokera
      Fault Code Fault Image System Behaviour
      _St N/A Autostop
      _CL N/A Call for service
      A01 Vokera Error PictureVokera Error Picture Ignition failure flame not sensed – internal fault
      A02 BellBell Limit thermostat fault
      A03 BellBell Fan fault
      A04 BellBell Insufficient system water pressure
      A06 BellBell Domestic how water (DHW) thermistor fault
      A07 Bell