39 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler is unable to measure the temperature of the water inside it, so it has safely shut down to prevent overheating.
Your boiler is struggling to accurately measure the temperature of the water returning to it, so it has stopped working to prevent potential overheating.
Your boiler has stopped working because it is unable to accurately measure the temperature of the water flowing through the system due to a faulty electrical connection or sensor.
Your boiler has stopped working because it is unable to accurately read the temperature of the water returning to it, causing it to shut down for safety.
Your boiler has lost the connection to the temperature sensor in your hot water cylinder, meaning it no longer knows how hot the water currently is.
Your boiler has detected that it is getting too hot and has automatically switched itself off to prevent any damage.
Your boiler has detected that the water pressure inside the system has dropped too low to operate safely.
Your boiler has detected that the water temperature is changing too drastically between different internal sensors, likely due to a flow issue, so it has safely turned itself off.
Your boiler has detected that the water inside it is heating up much faster than it should, so it has turned itself off as a safety precaution.
Your boiler has detected that the exhaust gases are becoming far too hot and has automatically switched itself off to prevent damage or dangerous overheating.
Your boiler has detected an issue with its flame monitoring system and has safely shut down to prevent gas from flowing without a confirmed flame.
Your boiler is failing to light the fuel inside, meaning it cannot produce heat or hot water because it hasn't detected a flame.
Your boiler is trying to start but the flame keeps going out, meaning it cannot produce heat or hot water.
Your boiler has detected that the internal fan responsible for clearing exhaust gases is not spinning at the correct speed to operate safely.
Your boiler's internal communication system is struggling to transmit data because the electrical signal between its components is too weak.
Your boiler has detected an issue with the component that manages the flow of gas, causing it to shut down for safety reasons.
Your boiler has detected an issue with the valve that controls the gas supply, causing it to shut down for safety reasons.
Your boiler's internal computer is experiencing a memory error, meaning it has lost its settings and cannot safely manage the heating process.
Your boiler has detected an internal computer processing error, causing it to shut down for safety reasons to prevent incorrect operation.
Your boiler has detected that its internal computer components are overheating, so it has safely shut itself down to prevent any damage.
Your boiler has detected an internal electronic error while trying to monitor the flame, causing it to shut down for safety.
Your boiler is struggling to keep the flame alight consistently, causing it to shut down for safety reasons.
Your boiler's computer has lost its identity settings, preventing it from knowing how to function correctly.
Your boiler has stopped working because it is unable to accurately measure the temperature of the water flowing through your heating system.
Your boiler has detected that the water temperature is behaving unexpectedly, suggesting that its internal heat sensors are likely providing conflicting or inaccurate information.
Your boiler's internal sensor that measures water pressure is malfunctioning or disconnected, preventing the system from knowing if it is safe to fire up.
Your boiler has detected an electrical fault with its internal water pressure sensor.
Your boiler is struggling to detect the water pressure needed to run safely, likely because the system is low on water or a sensor is performing incorrectly.
Your boiler has detected an issue with the drainage of exhaust gases or water, meaning it has shut down to prevent the release of harmful fumes into your home.
Your boiler is having trouble communicating with the controls that manage your hot water temperature.
Your boiler has detected that there is not enough water circulating inside the system to carry heat away safely.
Your boiler has detected a mix-up or incorrect reading between its internal temperature sensors, which usually means they were installed backwards or have come loose during maintenance.
Your boiler has detected that its internal temperature sensors are either disconnected or have been accidentally moved to the wrong pipes during installation or maintenance work.
Your boiler has detected that the connection to your underfloor heating system is interrupted or a safety sensor is not reporting correctly, so it has stopped providing heat to prevent damage.
Your boiler is failing to light because the internal sensor or wire that tells it to spark has a loose connection or a wiring issue.
Your boiler has detected an issue with the electrical connection to the internal gas valve, which controls the supply of gas for heating and hot water.
Your boiler has detected an issue with the water pump's wiring or connection, meaning it cannot circulate water properly to provide heating or hot water.
Your boiler's internal computer has failed its own safety check and can no longer control the heating system, meaning the unit will not operate.
Your boiler has automatically switched off because the water pressure inside the system has dropped too low.
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BoilerFaultCodes