39 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler's internal computer is unable to talk to its main control board, which has caused the system to stop functioning.
Your boiler's main internal computer and the front control panel have lost their connection, meaning the unit cannot receive instructions or show you what is happening.
Your boiler is struggling to push hot water through your radiators because the external pump that circulates the water is not working correctly.
Your boiler has lost the ability to read the temperature of the water inside it, so it has shut down to prevent overheating.
Your boiler has lost the signal from one of its internal temperature sensors, causing it to stop operating as a protective measure.
Your boiler has stopped working because a sensor that measures water temperature is providing an incorrect signal, so the system has safely shut down to prevent overheating.
Your boiler has stopped working because it is unable to accurately read the temperature of the water returning to it from your radiators.
Your boiler is struggling to detect the temperature of your hot water storage tank because a sensor connection is faulty.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler has detected that the water is getting hot far too quickly, so it has shut itself down to prevent internal damage.
Your boiler is shutting down because it is heating up much faster than it is moving the water around, which often points to a circulation problem.
Your boiler has detected that the exhaust gases are becoming dangerously hot and has shut itself down to prevent damage or overheating.
Your boiler has detected a signal that suggests a flame is present even when the burner is turned off, causing it to shut down for safety reasons.
Your boiler is trying to start up but is failing to light the fuel to produce a flame, so it has safely shut down to prevent gas buildup.
Your boiler is trying to stay lit but failing, which means it has stopped producing heat and hot water as a safety precaution.
Your boiler has detected an issue with the internal air-moving mechanism that controls the safe ventilation of gases, meaning it has automatically shut down to prevent unsafe operation.
Your boiler is having trouble communicating with its external controllers because the signal wire between them is experiencing an electrical issue.
Your boiler has detected an internal electrical issue preventing it from opening the gas valve, so it has safely shut itself down to prevent any unsafe operation.
Your boiler has detected that the gas valve is not closing properly when it should, so it has shut down as a safety precaution.
Your boiler's computer memory has experienced a critical error, meaning it can no longer remember its internal settings or run safely.
Your boiler has detected an internal communication error between its electronic components, meaning it has shut down as a precaution to prevent further damage.
Your boiler's main control unit has detected an electrical problem with its temperature sensors, meaning it has shut down as a precaution to prevent damage.
Your boiler's electronic control system is failing to correctly detect whether the burner is lit, so it has safely shut down to prevent gas from building up.
Your boiler is struggling to maintain a steady flame, causing it to shut down for safety reasons to prevent unburnt gas from building up.
Your boiler's computer has lost its internal identification settings, essentially forgetting which specific model it is, which prevents it from operating correctly.
Your boiler has detected that the water temperature readings are stuck or not changing as they should, so it has stopped running to prevent potential damage.
Your boiler has detected that the water temperature readings at the start and end of its heating circuit do not match up, causing it to shut down for safety.
Your boiler's water pressure sensor is providing an incorrect reading, which is preventing the system from confirming that there is enough water inside to operate safely.
Your boiler's internal water pressure sensor is sending an invalid electrical signal, meaning the system cannot accurately detect the pressure level.
Your boiler is struggling to detect a rise in system pressure when it turns on, which usually means there is either not enough water in your system or the sensor is struggling to read it correctly.
Your boiler has detected that parts inside are getting dangerously hot and has shut itself down to prevent any damage.
Your boiler is having trouble draining away the water it creates during normal operation, or it is sensing an issue with the exhaust air system.
Your boiler has detected that there is either insufficient water circulating inside it or that its internal temperature sensors are failing to register a rise in heat when the burner starts.
Your boiler has detected that a temperature probe is not fitted in the correct location, preventing the system from accurately measuring heat levels to operate safely.
Your boiler is failing to detect the flame because the internal sensors that manage the ignition process are disconnected or experiencing a wiring fault.
Your boiler has lost its connection to the component that controls the gas supply, meaning it cannot ignite and provide heat or hot water.
Your boiler has detected that the water pump currently fitted is not the correct type or compatible model intended for this system.
Your boiler has stopped working because the water pressure is too low for it to operate safely.
Your boiler's computer has lost its internal identification settings, which prevents it from knowing how to run your heating system properly.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes