17 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has failed to ignite because it cannot detect a flame, meaning it currently cannot heat your home or water.
Your boiler has failed to start because it cannot detect a flame or because your condensate drain pipe is blocked and backing up.
Your boiler has detected that it is overheating and has safely shut itself down to prevent internal damage.
Your boiler has detected an issue with an external control device, such as an external timer, thermostat, or heating programmer, which is preventing the system from operating correctly.
Your boiler has shut down because the water returning from your radiators is hotter than the boiler expects, which suggests a possible issue with the water flow through your system.
Your boiler has detected that hot water is flowing in the wrong direction or the sensors are misreading the temperature, causing it to shut down to prevent damage.
Your boiler is struggling to detect that the internal fan is spinning correctly, which causes it to shut down to prevent unsafe operation.
Your boiler has stopped working because the water pressure inside your heating system has dropped too low to operate safely.
Your boiler has stopped working because the water pressure inside your heating system has dropped too low to operate safely.
Your boiler has detected an internal electronic error that is preventing it from operating safely, requiring a qualified technician to investigate.
Your boiler's electronic brain is failing to recognise its own configuration settings, which is likely due to a loose internal connection or a fault with the main control board.
Your boiler has detected an internal configuration error where a tiny plastic link plug on the main circuit board is missing or loose, preventing it from starting up correctly.
Your boiler's temperature sensor is providing incorrect readings, which means the system has safely shut down to prevent it from overheating.
Your boiler is struggling to accurately measure the temperature of the water returning to it, so it has shut down as a precaution to prevent overheating.
Your boiler has detected that the water temperature is rising too quickly or is circulating poorly, so it has shut down to prevent internal overheating.
Your boiler has detected that the water inside the system is getting far too hot, or isn't circulating around your radiators properly, so it has shut down to prevent damage.
Your boiler has stopped working because the water pressure inside your heating system has dropped below the minimum level required to run safely.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes