Category
Boilers
Boiler fault codes with evidence-led diagnosis.
314 published entries
Brands in boilers
All brands
Published error entries
F28Vaillant boiler F28: no valid flame was detected during ignitionHigh· VaillantF29Vaillant boiler F29: the operating flame was lost and reignition failedHigh· VaillantF32Vaillant F.32 on a gas boiler: fan faultHigh· VaillantF33Vaillant F.33 on a gas water heater: air pressure switch errorHigh· VaillantF35Vaillant F35 on a gas boiler: air and flue duct faultHigh· VaillantF37Vaillant F.37 on a gas water heater: fan speed deviationHigh· VaillantF42Vaillant F42 on a gas boiler: gas coding resistor faultHigh· VaillantF54Vaillant F54 fault: insufficient gas supply at boiler startHigh· VaillantF55Vaillant F55 on a gas boiler: carbon monoxide sensor faultHigh· VaillantF56Vaillant F56 on a gas boiler: carbon monoxide limit exceededHigh· VaillantF57Vaillant F57 boiler fault: comfort mode combustion errorHigh· VaillantF61Vaillant boiler F61: gas-valve control did not operate in its required timingHigh· VaillantF62Vaillant boiler F62: flame switch-off was detected after the allowed delayHigh· VaillantF64Vaillant F.64 on a gas boiler: electronics or sensor faultHigh· VaillantF67Vaillant F.67 on a gas boiler: implausible flame signalHigh· VaillantF68Vaillant F.68 on a gas boiler: unstable flame signalHigh· VaillantF70Vaillant boiler F70: appliance coding does not match the installed control hardwareHigh· VaillantF72Vaillant boiler F72: flow and return sensors report an implausible differenceHigh· VaillantF75Vaillant boiler F75: the pressure sensor did not detect the expected change when the pump startedHigh· VaillantF77Vaillant F.77 on a gas boiler: flue flap or condensate pumpHigh· VaillantF83Vaillant F83 fault: too little temperature rise after burner startHigh· Vaillant347Viessmann 347 on a Vitodens boiler: flue gas recirculationHigh· Viessmann357Viessmann 357 on a Vitodens boiler: insufficient gas supplyHigh· Viessmann65Viessmann 65 on a Vitodens boiler: no flame signal at startHigh· ViessmannF4Viessmann F4: confirm the boiler model firstHigh· ViessmannC6Worcester C6 on a gas boiler: fan speed too lowHigh· Worcester BoschE9Worcester E9 on a gas boiler: safety temperature limiter trippedHigh· Worcester BoschEAWorcester EA fault: flame not detectedHigh· Worcester BoschEoFA. O. Smith EoF on a hybrid heat pump water heater: condensate pump failureMedium· A. O. Smith042Ariston 042 on a Nuos Plus heat pump water heater: evaporator blockedMedium· Ariston051Ariston 051 on a Nuos Plus heat pump water heater: high pressure in the heat pumpMedium· Ariston10Ariston 10 on a Velis water heater: outlet temperature probe open or short circuitedMedium· Ariston108Ariston 108 on a gas boiler: water pressure too lowMedium· Ariston14Ariston 14 on a Velis water heater: powered heating element fails to heatMedium· Ariston141Ariston 141 on a Lydos Hybrid water heater: fan problemMedium· Ariston201Ariston error 201 on a gas boiler: water circuit faultMedium· Ariston230Ariston 230 on a Nuos Plus heat pump water heater: water temperature sensor near the elementMedium· Ariston240Ariston 240 on Lydos Hybrid heater: anode short circuitMedium· Ariston241Ariston 241 on a Nuos Plus heat pump water heater: impressed current anode open circuitMedium· Ariston304Ariston 304 on a gas boiler: too many resets in 15 minutesMedium· AristonA.02.06Baxi A.02.06 on a gas boiler: low heating pressure warningMedium· BaxiA.02.33Baxi A.02.33 on a gas boiler: automatic fill warningMedium· BaxiE.02.39Baxi E.02.39 on a gas boiler: filling misses minimum pressureMedium· BaxiE109Baxi E109 on a gas boiler: air in the boiler circuitMedium· BaxiE117Baxi E117 on a gas boiler: circuit pressure too highMedium· BaxiE118Baxi E118 on a gas boiler: water pressure too lowMedium· BaxiE178Baxi E178 on a gas boiler: overheat on low temperature systemMedium· BaxiE19Baxi E19 on a gas boiler: fault while filling the circuitMedium· Baxi