BoilerBuddy · fault code lookup
Vaillant fault codes — in plain English.
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Vaillant · ecoTEC plus
- Vaillant F.00F.00 indicates flow temperature sensor interruption. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.01F.01 indicates return temperature sensor interruption. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.02F.02 indicates DHW outlet sensor interruption. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.03F.03 indicates cylinder temperature sensor interruption. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.10F.10 indicates flow temperature sensor short circuit. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.11F.11 indicates return temperature sensor short circuit. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.12F.12 indicates DHW outlet sensor short circuit. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.13F.13 indicates cylinder temperature sensor short circuit. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.20F.20 indicates safety switch-off: temperature limiter. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.23F.23 indicates safety switch-off: temperature spread too large. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.25F.25 indicates safety switch-off: flue temperature too high. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.26F.26 indicates fuel valve not working. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.27F.27 indicates safety switch-off: flame simulation. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.32F.32 indicates fan fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.42F.42 indicates coding resistor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.49F.49 indicates eBUS fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.52F.52 indicates mass flow sensor not connected. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.53F.53 indicates gas valve assembly mass flow unexpected. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.54F.54 indicates boiler-start fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.55F.55 indicates CO sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.56F.56 indicates safety switch-off: CO limit exceeded. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.57F.57 indicates measuring-program fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.61F.61 indicates fuel-valve actuation fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.62F.62 indicates fuel-valve switch-off delay fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.63F.63 indicates EEPROM fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.64F.64 indicates electronics/sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.65F.65 indicates electronics temperature fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.67F.67 indicates electronics/flame fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.68F.68 indicates unstable flame-signal fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.70F.70 indicates invalid Device Specific Number fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.71F.71 indicates flow temperature sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.72F.72 indicates flow/return temperature sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.73F.73 indicates water pressure sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.74F.74 indicates water pressure sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.77F.77 indicates flue non-return valve/condensate pump fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.78F.78 indicates DHW outlet sensor interruption at an external controller. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.80F.80 indicates actoSTOR inlet sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.81F.81 indicates cylinder charging pump fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.82F.82 indicates external current anode fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.83F.83 indicates NTC temperature gradient fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.84F.84 indicates implausible NTC temperature difference fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.85F.85 indicates NTCs fitted incorrectly. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.90F.90 indicates communication with actoSTOR interrupted. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.91F.91 indicates actoSTOR sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.92F.92 indicates incorrect gas type fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.93F.93 indicates gas-route/combustion-quality fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.94F.94 indicates vortex and differential-pressure fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant Communication faultThe manual lists a communication fault between the display and the PCB in the electronics box. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.28Start-up failure: ignition was unsuccessful; the gas-pressure monitor or thermal cut-out may have been triggered. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.29Operating failure: re-ignition was unsuccessful; an intermittent interruption to the gas supply is one possible cause. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.75The boiler detected no expected pressure change when the pump started; the manual associates this with a pump fault or water shortage. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.24F.24 indicates that the temperature is increasing too quickly. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.22F.22 indicates insufficient water in the heating system and the boiler has stopped to protect itself. The manual notes that some shared-table codes may not be visible on every product variant.
Vaillant · ecoTEC pro
- Vaillant F.00F.00 indicates flow temperature sensor interruption. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.01F.01 indicates return temperature sensor interruption. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.10F.10 indicates flow temperature sensor short circuit. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.11F.11 indicates return temperature sensor short circuit. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.20F.20 indicates safety switch-off: temperature limiter. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.23F.23 indicates safety switch-off: temperature spread too large. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.24F.24 indicates safety switch-off: temperature increase too fast. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.25F.25 indicates safety switch-off: flue temperature too high. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.26F.26 indicates fuel valve not working. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.27F.27 indicates safety switch-off: flame simulation. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.32F.32 indicates fan fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.49F.49 indicates eBUS fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.61F.61 indicates fuel-valve actuation fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.62F.62 indicates fuel-valve switch-off delay fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.63F.63 indicates EEPROM fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.64F.64 indicates electronics/sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.65F.65 indicates electronics temperature fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.67F.67 indicates electronics/flame fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.68F.68 indicates unstable flame-signal fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.70F.70 indicates invalid Device Specific Number fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.71F.71 indicates flow temperature sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.72F.72 indicates flow/return temperature sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.73F.73 indicates water pressure sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.74F.74 indicates water pressure sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.77F.77 indicates flue non-return valve/condensate pump fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.78F.78 indicates DHW outlet sensor interruption at an external controller. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.83F.83 indicates NTC temperature gradient fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.84F.84 indicates implausible NTC temperature difference fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.85F.85 indicates NTCs fitted incorrectly. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant Communication faultThe manual lists a communication fault between the display and the PCB in the electronics box. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.22F.22 indicates low water pressure in the heating installation and the boiler has stopped to protect itself. The manual notes that some shared-table codes may not be visible on every product variant.
- Vaillant F.28F.28 indicates that the ecoTEC pro could not establish a flame after three ignition attempts and has entered fault mode. The manual notes that some shared-table codes may not be visible on every product variant.
- Vaillant F.29F.29 indicates an operating failure after unsuccessful re-ignition, associated with intermittent interruption of the gas supply. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.75F.75 indicates a pump or water shortage because the pressure increase is insufficient when the pump starts. The manual warns that some shared-table codes may not be visible on every product variant.
Vaillant · ecoTEC exclusive
- Vaillant F.00F.00 indicates flow temperature sensor interruption. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.01F.01 indicates return temperature sensor interruption. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.02F.02 indicates DHW outlet sensor interruption. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.03F.03 indicates cylinder temperature sensor interruption. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.10F.10 indicates flow temperature sensor short circuit. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.11F.11 indicates return temperature sensor short circuit. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.12F.12 indicates DHW outlet sensor short circuit. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.13F.13 indicates cylinder temperature sensor short circuit. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.20F.20 indicates safety switch-off: temperature limiter. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.22F.22 indicates safety switch-off: low water pressure. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.23F.23 indicates safety switch-off: temperature spread too large. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.24F.24 indicates safety switch-off: temperature increase too fast. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.25F.25 indicates safety switch-off: flue temperature too high. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.26F.26 indicates fuel valve not working. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.27F.27 indicates safety switch-off: flame simulation. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.28F.28 indicates start-up failure: ignition unsuccessful. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.29F.29 indicates operating failure: ignition unsuccessful. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.32F.32 indicates fan fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.33F.33 indicates air/flue gas pressure implausible. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.35F.35 indicates air/flue gas duct fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.42F.42 indicates coding resistor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.49F.49 indicates eBUS fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.55F.55 indicates CO sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.56F.56 indicates safety switch-off: CO limit exceeded. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.57F.57 indicates measuring-program fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.61F.61 indicates fuel-valve actuation fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.62F.62 indicates fuel-valve switch-off delay fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.63F.63 indicates EEPROM fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.64F.64 indicates electronics/sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.65F.65 indicates electronics temperature fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.67F.67 indicates electronics/flame fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.68F.68 indicates unstable flame-signal fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.70F.70 indicates invalid Device Specific Number fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.71F.71 indicates flow temperature sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.72F.72 indicates flow/return temperature sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.73F.73 indicates water pressure sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.74F.74 indicates water pressure sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.75F.75 indicates pump/water shortage fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.77F.77 indicates flue non-return valve/condensate pump fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.78F.78 indicates DHW outlet sensor interruption at an external controller. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.80F.80 indicates actoSTOR inlet sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.81F.81 indicates cylinder charging pump fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.82F.82 indicates external current anode fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.83F.83 indicates NTC temperature gradient fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.84F.84 indicates implausible NTC temperature difference fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.85F.85 indicates NTCs fitted incorrectly. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.90F.90 indicates communication with actoSTOR interrupted. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.94F.94 indicates vortex and differential-pressure fault. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant Communication faultThe manual lists a communication fault between the display and the PCB in the electronics box. The manual warns that some shared-table codes may not be visible on every product variant.
Vaillant · ecoFIT pure
- Vaillant F.10Short circuit: Flow temperature sensor
- Vaillant F.11Short circuit: Return temperature sensor
- Vaillant F.49eBUS fault: Voltage too low
- Vaillant F.63Fault: EEPROM
- Vaillant F.64Fault: Electronics / sensor / analogue-to-digital converter
- Vaillant F.65Fault: Electronics temperature too high
- Vaillant F.71Fault: Flow/return temperature sensor
- Vaillant F.72Fault: Deviation in the water pressure sensor/return temperature sensor
- Vaillant F.73Fault: Water pressure sensor not connected or has short-circuited
- Vaillant F.74Fault: Electrical problem in the water pressure sensor
- Vaillant F.84Fault: Flow/return temperature sensor
- Vaillant F.85Fault: Temperature sensor
- Vaillant F.22F.22 indicates low water pressure in the heating installation and the boiler has stopped to protect itself.
- Vaillant F.28F.28 indicates that the ecoFIT pure could not establish a flame after three ignition attempts and has entered fault mode.
- Vaillant F.00Fault: Flow temperature sensor
- Vaillant F.01Fault: Return temperature sensor
- Vaillant F.20Safety shutdown: Overheating temperature reached
- Vaillant F.23Safety shutdown: Temperature spread too great (NTC1/NTC2)
- Vaillant F.24Safety shutdown: Temperature rise too fast
- Vaillant F.32Fan frost protection function active: Fan speed outside the tolerance values
- Vaillant F.83Fault: Dry fire
- Vaillant F.25Safety shutdown: Flue gas temperature too high. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.27Safety shutdown: Fault in flame detection (listed causes include a leaking gas solenoid valve). The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.61Fault: Gas valve assembly control. The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.62Fault: Gas valve switch-off control (listed causes include a leaking gas valve assembly and delayed extinguishing of the flame signal). The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.77Fault: Condensate or smoke (flue non-return flap defective). The manual warns that some shared-table codes may not be visible on every product variant.
- Vaillant F.29F.29 indicates flame loss.
- Vaillant F.75F.75 indicates a defective pressure switch.
Vaillant · ecoTEC sustain
- Vaillant F.00Fault: Flow temperature sensor
- Vaillant F.01Fault: Return temperature sensor
- Vaillant F.10Short circuit: Flow temperature sensor
- Vaillant F.11Short circuit: Return temperature sensor
- Vaillant F.22Safety shutdown: Water deficiency in the boiler
- Vaillant F.46Short circuit: Additional temperature sensor at the water inlet (installed solar set, optional)
- Vaillant F.49eBUS fault: Voltage too low
- Vaillant F.63Fault: EEPROM
- Vaillant F.64Fault: Electronics / sensor / analogue-to-digital converter
- Vaillant F.65Fault: Electronics temperature too high
- Vaillant F.71Fault: Flow/return temperature sensor
- Vaillant F.72Fault: Deviation in the water pressure sensor/return temperature sensor
- Vaillant F.73Fault: Water pressure sensor short-circuited
- Vaillant F.74Fault: Water pressure sensor not connected
- Vaillant F.75Fault: Pump/water deficiency
- Vaillant F.84Fault: Flow/return temperature sensor (values not consistent)
- Vaillant F.85Fault: Temperature sensor
Look up a fault code
Enter the code as it appears on your Vaillant boiler display. We show published, verified entries for the matching range.