47 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has detected an issue with the flame sensing system, which is preventing it from operating safely.
Your boiler has failed to light the flame after several attempts and has safely shut itself down to prevent a gas build-up.
Your boiler is detecting a signal that suggests a flame is present even though it has not yet attempted to light, so it has stopped for safety reasons.
Your boiler is failing to detect the flame after it lights, so it is turning itself off to ensure your safety.
Your boiler has experienced a power cut while it was already trying to recover from a serious internal safety fault, meaning it is currently unable to restart safely.
Your boiler has stopped because a safety device or an external control, like a thermostat, is not sending the signal needed to start it up.
Your boiler's main computer control unit is reporting a serious internal hardware failure, meaning it can no longer safely operate your heating or hot water.
Your boiler has detected a disconnection in the electrical connection that controls the flow of gas, causing it to shut down for safety.
Your boiler's internal computer or its communication module has developed a critical fault, preventing it from safely starting or controlling your heating and hot water.
The internal computer board of your boiler has developed a serious fault and can no longer control the heating process.
Your boiler's computer system has encountered an internal technical failure, meaning it can no longer safely operate or heat your home.
Your boiler's internal computer is experiencing a major electronic failure, preventing it from starting or maintaining its normal operation.
Your boiler's internal computer is experiencing a critical failure and can no longer control the system safely.
Your boiler has detected an internal failure within its main control computer, meaning the appliance cannot safely operate and must be shut down.
Your boiler is struggling to ignite the gas needed to create heat and has stopped trying after running for too long without success.
Your boiler has detected a failure within its main internal computer or communication module, which means the system is unable to safely manage its own controls.
Your boiler's main internal computer has developed a critical internal error and can no longer safely control the heating system.
Your boiler has detected that it is still trying to burn gas even though it should have turned off, so it has locked itself for safety.
Your boiler is struggling to read the outdoor temperature, meaning it cannot automatically adjust your home's heating levels based on the weather.
Your boiler has lost its internal clock settings, likely due to a recent power cut, and needs to be reset to ensure your heating schedule works correctly.
Your boiler has lost its internal clock settings, likely due to a recent power cut, and needs to be reset to allow it to operate correctly.
Your boiler's wall-mounted heating controller is having trouble reading the room temperature, which may cause your heating to run at the wrong times or not start as expected.
Your boiler is having trouble detecting the temperature of the water it is heating for your taps and shower, likely due to a loose wire or a faulty sensor.
Your boiler is having trouble communicating with an internal sensor that monitors your hot water temperature.
Your boiler is failing to heat your water, likely due to a loose wire or a faulty sensor that is preventing the system from identifying the water temperature correctly.
Your boiler is struggling to complete a routine safety cycle intended to kill bacteria in the hot water system, likely because it cannot properly regulate the temperature or flow of the water.
Your boiler has detected a faulty electrical connection or a broken sensor that monitors its internal water flow, causing it to stop working for safety reasons.
Your boiler has lost communication with its control system, causing it to shut down for safety because it cannot correctly interpret temperature or operating signals.
Your boiler is currently struggling to communicate with your wall-mounted heating controller, meaning it hasn't been set up correctly to read your home's temperature.
Your boiler is not communicating with its wall-mounted thermostat control, so it does not know what temperature you want your home to be.
Your boiler's control panel is trying to trigger cold-weather protection settings, but it cannot find the remote sensor it needs to monitor the temperature.
Your boiler's control panel is looking for a remote thermostat that isn't connected, even though it is currently trying to run a frost protection program.
Your boiler's control system is confused because two different control panels are trying to act as the 'boss' at the same time.
Your boiler's outside temperature sensor is sending a faulty signal, which may cause your heating system to work less efficiently or struggle to reach your desired room temperature.
Your boiler is struggling because it has lost the signal from the weather sensor that tells it how cold it is outside.
Your boiler's internal sensor that detects water pressure has stopped working, meaning the system can no longer accurately read how much water is inside.
Your boiler is struggling to communicate with its wall-mounted thermostat control panel, which means it doesn't know what temperature to set.
Your boiler has detected a faulty connection or wiring issue with one of its internal safety sensors, which is preventing it from operating correctly.
Your boiler's smart controls are confused because two separate controllers are both trying to act as the primary brain of the heating system at the same time.
Your boiler is having trouble 'talking' to its external heating controller, which means it cannot receive instructions to turn the heating on.
Your boiler's wall-mounted heating controller is having trouble reading the room temperature, which may cause your heating system to behave unpredictably.
Your boiler is struggling to detect the flow of water because of a faulty connection or a damaged sensor, which will prevent your heating and hot water from working correctly.
Your boiler has detected that the water returning to it from your radiators is dangerously hot, causing it to shut down to prevent damage.
Your boiler's temperature sensing system is experiencing an electrical connection issue, causing it to stop operating correctly to protect itself.
Your boiler has detected a critical failure in its internal computer systems, meaning it cannot operate safely and will have shut down.
Your boiler's internal electronic control system has experienced a critical hardware failure and can no longer communicate correctly to operate your heating.
Your boiler is signalling an issue with the water pressure level, either because it has become too high or the sensor is failing to read it correctly.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes