So your boiler is flashing and it's showing a random set of numbers and letters? This is an error code, and each error code is specific to the error. So, on this page we have compiled a database of almost every mainstream boiler and their error codes. Have a look to see if you can find your one, you may save yourself some time and money before arranging for a callout. If you cant find your error code then give us a call.
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. |
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. |
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 t |