26 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has shut down because it detected that exhaust gases are not being properly cleared outwards, which is a safety feature to prevent fumes from entering your home.
Your boiler has stopped working because the water pressure inside the system is too low.
Your boiler has detected that there is too much water pressure in the system, which can cause the safety valves to trigger or the unit to stop working.
Your boiler's hot water sensor is not working correctly, meaning your taps might not get hot or the temperature could be inconsistent.
Your boiler has detected a problem with the sensor that monitors the temperature of the water leaving the unit, meaning it cannot operate safely or effectively.
Your boiler is failing to light or stay lit because it cannot detect a flame, which has caused the system to shut down for safety.
Your boiler has overheated, causing it to shut down automatically to protect the internal components.
Your boiler is struggling to detect a flame, which means it cannot safely stay lit to provide heating or hot water.
Your boiler has stopped working because water isn't flowing through the system as it should, likely due to a stuck or faulty pump.
Your boiler has detected an issue with an internal sensor meant for additional system monitoring, which is usually caused by a connection error or a software setting mismatch.
Your boiler has lost communication with the component that controls the gas supply, meaning it won't be able to light the flame to provide heating or hot water.
Your boiler's computer has been set up with the wrong internal settings, causing it to shut down because it doesn't recognize how its air supply is configured.
Your boiler has detected that the exhaust gases have reached an unsafe temperature and has shut down as a safety precaution.
Your boiler has detected an issue with the sensor that monitors exhaust gases, which has caused the system to shut down for safety.
Your boiler has stopped working because its internal fan is unable to communicate with the main control board.
Your boiler has detected that the water drain for condensation is backed up, meaning waste water cannot leave the system.
Your boiler has been reset too many times in a short period and has temporarily locked itself for safety.
Your boiler has shut down because the electrical supply from the grid has dropped to a level that is too low for it to operate safely.
Your boiler has detected an issue with the electrical power supply frequency coming into your home, which is preventing it from running safely.
Your boiler has tried to start several times but cannot maintain a flame, meaning it has locked itself out for safety.
Your boiler has detected that one of its control buttons is stuck or faulty, which is preventing you from changing settings or operating the unit properly.
Your boiler is having trouble communicating with your thermostat or smart controller, meaning it might not know when to turn on or off.
Your boiler has detected that a temperature sensor isn't correctly touching the pipe it needs to monitor, preventing it from reading the water temperature accurately.
Your boiler has detected an issue with the air or gas mixture during ignition and has shut down for safety.
Your boiler is struggling to burn gas properly and has likely locked out for safety after multiple failed ignition attempts.
Your boiler has shut down because it has detected a blockage or restriction in the flue pipe that safely carries exhaust fumes outside.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes