Vaillant ecoTEC plus fault codes
Built 2005 onwards
The volume seller. Codes are identical across the run, but the pressure sensor moved position in the 2015 revision, which changes how an engineer diagnoses F.75.
Codes on the ecoTEC plus follow the same Vaillant scheme as the rest of the range. Where a code behaves differently on this generation, the code page says so.
Fault codes
All Vaillant codes that apply to this model.
- F.22The boiler has shut down because there is not enough water in the system. Pressure has dropped below roughly 0.5 bar and it will not fire until you top it up.Get it checked
- F.75The boiler cannot detect a rise in pressure when the pump starts, so it has locked out. Usually a failed pressure sensor or a pump that is not moving water.Get it checked
- F.28The boiler tried to light and failed three times in a row, so it has shut the gas off and locked out. Do not keep resetting it.Stop — call an engineer
- F.29The boiler lit correctly and then lost the flame while it was running. It has shut the gas off and locked out, and it needs an engineer.Stop — call an engineer
- F.20The overheat thermostat has tripped because the boiler got too hot. It has shut down to protect itself and it should not be restarted repeatedly.Stop — call an engineer
- F.32The fan is not running at the speed the boiler expects, so combustion cannot be verified as safe and the boiler has locked out.Get it checked
- F.23The gap between flow and return temperature is too wide. Vaillant call it water shortage, and it nearly always means the pump is not moving enough water.Get it checked
- F.62The gas valve is not shutting off when the boiler tells it to. This is a gas safety fault and the boiler must not be used until an engineer has seen it.Stop — call an engineer
- F.35The air intake or flue is blocked. Something is physically obstructing the path combustion products take out of the building.Get it checked
- F.73The pressure sensor signal is out of range at the low end. Usually the sensor or its wiring, rather than the pressure itself.Get it checked
- F.24Temperature is rising faster than it should when the burner fires. That is a circulation problem caught a step earlier than an overheat.Get it checked
- F.61The gas valve control circuit has faulted. The boiler will not fire and this is firmly an engineer's job.Get it checked
- F.27The boiler is detecting a flame when the burner should be off. Switch it off and get a Gas Safe engineer out rather than resetting it.Stop — call an engineer
- F.54A gas supply fault, usually shown alongside F.28 or F.29. It means gas is reaching the appliance at too low a pressure.Get it checked