34 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your heater has stopped working because the fan that safely clears exhaust gases is not spinning or receiving power.
Your boiler is attempting to start but failing to ignite the flame, so it has shut down as a safety precaution.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.
Your boiler has stopped working as a safety precaution and will not restart, which means you currently have no heating or hot water.
Your boiler has detected that water is not moving through the system properly, which is preventing it from heating your home safely.
Your boiler has detected that the internal fan responsible for clearing exhaust gases is not spinning correctly or cannot communicate with the main control board.
Your boiler has stopped heating because it is struggling to accurately read the temperature of the water circulating through your radiators.
Your boiler is struggling to accurately measure the temperature of your hot water, which may lead to the system shutting down to prevent overheating.
Your boiler's outdoor sensor, which helps it adjust your heating based on the weather, is sending an incorrect or missing signal.
Your boiler has detected a break in the electrical connection for the part that monitors flue gas temperatures, causing it to shut down for safety reasons.
Your boiler has detected an issue with the sensor that monitors the exhaust gases, meaning it has safely shut down to prevent unsafe operation.
Your boiler is confused because it senses a flame inside when it shouldn't, so it has safely shut itself down to prevent any issues.
Your boiler's internal temperature monitor is not sending a proper signal, which prevents the unit from heating your home reliably.
Your boiler has detected that it is running much too hot and has automatically shut itself down to prevent any damage or safety issues.
Your boiler has detected that the water is getting much hotter than it should as it travels through the system, suggesting a blockage or a failure in how the water circulates.
Your boiler has detected that the water temperature is rising too quickly or unevenly, causing it to shut down to prevent internal overheating.
Your boiler has detected that water is not moving through the system as expected when it tries to start up, so it has stopped for safety reasons.
Your boiler is struggling to move water through your heating system, which is preventing it from producing heat.
Your boiler is struggling to accurately measure the temperature of the incoming cold water, which may cause your hot water to be inconsistent or unavailable.
Your boiler's internal temperature sensor is failing to provide a reading, meaning the unit cannot safely manage its water temperature and has shut down to prevent damage.
Your boiler has stopped working because it cannot light the flame or keep it burning safely.
Your boiler is failing to detect the water pressure inside the system because the sensor is disconnected or faulty, which is preventing it from safely heating your home.
Your boiler's main internal computer has developed a programming error or is not communicating correctly with the rest of the unit.
Your heater is trying to turn on but cannot light the burner, meaning your heating will not work until the system is reset or repaired.
Your boiler has stopped working because the water pressure inside the system has dropped too low for it to operate safely.
Your boiler is not firing up because it isn't receiving the correct signal from your thermostat or internal controllers to start the heating process.
Your boiler has detected that the water pressure is too low for it to operate safely, which is why it has stopped working.
Your boiler has detected a problem with the sensor that monitors the safety of the exhaust gases, and it has shut down to prevent overheating.
Your boiler is unable to release gas into the burner to create a flame, meaning your heating will not work.
Your boiler has tried to start but cannot light the flame, causing it to shut down for safety.
Your boiler has lost power entirely, which is usually caused by a tripped switch at the fuse box or a fault with the electrical supply to the unit.
Your boiler is receiving power but fails to respond when the heating is scheduled to turn on, likely due to a communication failure between the controls and the unit.
Your boiler has become too hot and has automatically shut down to prevent damage to the internal components.
Your boiler has switched itself off because it has become too hot and needs time to cool down safely.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes