21 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has detected a flame signal when it shouldn't be there, which has caused it to shut down for safety purposes.
Your boiler has lost power to its internal electrical control circuit, meaning it cannot communicate with its parts or operate at all.
Your boiler is failing to light or cannot detect the flame, meaning it has shut down to prevent unburned gas from building up.
Your boiler has experienced a power disruption while it was already trying to report a serious internal error, causing it to lock itself for safety.
Your boiler has detected a blockage or a mechanical failure in the system that moves air in and out of the unit, causing it to shut down for safety.
Your boiler's internal electronic protection has triggered and the unit has completely lost power due to a failed internal fuse.
Your boiler has shut down because the water inside has become too hot, usually due to a lack of circulation or a blockage.
Your boiler has shut down because the water returning to the unit is too hot, meaning heat isn't being transferred properly to your radiators or taps.
Your boiler has detected that hot water is moving in the wrong direction or the temperature sensors have been confused, causing the system to shut down for safety.
Your boiler is overheating because water isn't moving through the system quickly enough to carry the heat away.
Your boiler has stopped working because the fan that removes waste gases cannot start or is not being powered correctly.
Your boiler's fan is running continuously because the internal control computer and the fan are not communicating correctly.
Your boiler has shut down because the water is not circulating properly, causing it to overheat too quickly.
Your boiler has stopped working because it has detected a fault with the internal sensor that monitors the temperature of the water leaving the unit.
Your boiler has detected a technical fault with the sensor that monitors water returning to the unit, causing the system to shut down as a safety precaution.
Your boiler has detected that a key internal thermometer is broken or disconnected, meaning it cannot safely monitor the temperature of the water leaving the unit.
Your boiler has stopped working because it cannot correctly measure the temperature of the water returning to the unit.
Your boiler's computer memory has incorrect settings or corrupted data, causing it to stop running for safety.
Your boiler has detected that a safety sensor meant to monitor air flow is stuck or blocked, preventing the system from starting up safely.
Your boiler is struggling to accurately measure the temperature of the water returning to it, so it has stopped operating to ensure your safety.
Your boiler has stopped working because its internal computer has detected a problem with the electronic circuit that manages the flame.
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BoilerFaultCodes