Category
Boilers
Boiler fault codes with evidence-led diagnosis.
314 published entries
Brands in boilers
All brands
Published error entries
E1Junkers E1 on gas water heater: outlet water overheatingHigh· JunkersE4Junkers E4 gas water heater: flue gas leak, casing overheatHigh· JunkersE5Junkers E5 on a gas boiler: flow temperature over the limitHigh· JunkersE9Junkers E9 on a gas boiler: temperature limiter trippedHigh· JunkersEAJunkers EA on a gas boiler: no flame detectedHigh· JunkersEEJunkers EE on gas water heater: modulation solenoid faultHigh· JunkersF0Junkers F0 on a gas boiler: internal electronics faultHigh· JunkersF7Junkers F7 on a gas boiler: flame detected with the appliance offHigh· JunkersFAJunkers FA on a gas boiler: flame still detected after gas shut-offHigh· JunkersFbJunkers FB boiler code: gas valve failed its leak testHigh· JunkersA01Lamborghini A01 on a gas boiler: burner does not igniteHigh· Lamborghini CaloreclimaE003Navien E003 on a tankless water heater: ignition failureHigh· NavienE004Navien E004 on a tankless water heater: false flame detectionHigh· NavienE012Navien E012 on a tankless water heater: flame lossHigh· NavienE016Navien E016 on a tankless water heater: heat exchanger overheatingHigh· NavienE030Navien E030 on a tankless water heater: exhaust overheatingHigh· NavienE110Navien E110 on a tankless water heater: abnormal air pressureHigh· NavienE1Rheem E1 on gas water heater: burner ignition fault lockoutHigh· RheemE6Rheem E6 on gas water heater: water overtemperature lockoutHigh· Rheem10Rinnai 10 on a tankless water heater: air supply or exhaust blockageHigh· Rinnai11Rinnai 11 on a tankless water heater: no ignitionHigh· Rinnai12Rinnai 12 on a tankless water heater: flame failureHigh· Rinnai14Rinnai 14 on a tankless water heater: overheat safety trippedHigh· RinnaiF01Saunier Duval F01 on gas water heater: water above 85 °CHigh· Saunier DuvalF04Saunier Duval F04 on a gas water heater: ignition failureHigh· Saunier DuvalF05Saunier Duval F05 on a gas water heater: air or flue faultHigh· Saunier DuvalF20Saunier Duval F20 on a Thema NOx: overheating faultHigh· Saunier DuvalF26Saunier Duval F.26 on a gas boiler: gas valve not workingHigh· Saunier DuvalF27Saunier Duval F.27 on a gas boiler: incorrect flame detectionHigh· Saunier DuvalF28Saunier Duval Thema NOx Boiler F28: Ignition Fault LockoutHigh· Saunier DuvalF29Saunier Duval F29 on a Thema NOx: ignition failureHigh· Saunier DuvalF32Saunier Duval F.32 on a gas boiler: fan faultHigh· Saunier DuvalF33Saunier Duval F33 on a Thema NOx: air flow faultHigh· Saunier DuvalF53Saunier Duval F.53 on a gas boiler: Venturi flow sensor faultHigh· Saunier DuvalF54Saunier Duval F.54 on a gas boiler: gas pressure faultHigh· Saunier DuvalF61Saunier Duval F.61 on a gas boiler: gas valve control faultHigh· Saunier DuvalF62Saunier Duval F.62 on a gas boiler: delayed gas valve shut offHigh· Saunier DuvalF68Saunier Duval F.68 on a gas boiler: unstable flame signalHigh· Saunier DuvalF75Saunier Duval F75 boiler: pressure sensor or pump faultHigh· Saunier DuvalF77Saunier Duval F77 boiler code: flue flap or condensate pump faultHigh· Saunier DuvalF171Vaillant F.171 on a gas water heater: fan or flue faultHigh· VaillantF20Vaillant boiler F20: safety temperature limiter detected excessive flow or return temperatureHigh· VaillantF22Vaillant boiler F22: too little heating water or system pressureHigh· VaillantF23Vaillant boiler F23: flow and return temperature difference is too largeHigh· VaillantF24Vaillant boiler F24: flow temperature is rising faster than the safe gradientHigh· VaillantF25Vaillant F.25 on a gas boiler: flue gas temperature too highHigh· VaillantF26Vaillant F.26 on a gas boiler: gas valve not workingHigh· VaillantF27Vaillant boiler F27: a flame signal exists while the gas valve should be closedHigh· Vaillant