33 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler is trying to start but the flame is not catching, so it has shut down for safety to prevent gas from building up.
Your boiler has detected that it is running much too hot and has automatically shut itself down to prevent damage or fire risk.
Your boiler has detected that the exhaust gases leaving the system are dangerously hot and has shut itself down to prevent damage or overheating.
Your boiler has lost the secure electrical connection required to tell the gas supply when to turn on, meaning it cannot ignite to provide heat or hot water.
Your boiler is failing to register the flow of water because of a faulty electronic sensor, meaning it has switched itself off to prevent overheating.
Your boiler has detected that its electrical components are not connected correctly, preventing it from starting up safely.
Your boiler has attempted to restart itself too many times after encountering previous errors and has now locked itself out as a safety precaution.
Your boiler has stopped working because the water pressure inside your heating system has dropped too low to operate safely.
Your boiler has lost connection with the sensor that monitors the temperature of your hot water cylinder, meaning it may not know when to heat your water.
Your boiler’s internal computer is confused about how it is set up and is unable to operate because it detects a mismatch between its configuration settings and the hardware it sees.
Your boiler has stopped working because the internal fan, which safely helps the system breathe and clear exhaust gases, is not spinning correctly.
Your boiler is struggling to detect the flame needed to heat your water, even if the burner has successfully lit.
Your boiler has detected a problem with the sensor that monitors the temperature of the water returning from your radiators.
Your boiler has detected that one of the buttons on the control panel is stuck or faulty, preventing you from changing settings.
Your boiler has detected that water is not moving through the system quickly enough to prevent it from overheating.
Your boiler has detected a problem with the sensor that monitors exhaust gases, and it has shut down for safety purposes.
Your boiler has lost its connection with the thermostat or control panel, meaning it cannot receive instructions to turn on or off.
Your boiler has stopped working because the electricity supply coming into the unit has dropped below the minimum level required to operate safely.
Your boiler has started an ignition process but lost its flame unexpectedly, causing the system to shut down for safety.
Your boiler has lost the signal that confirms a flame is burning, so it has shut down for safety.
Your boiler is overheating because the water is not flowing through the system as quickly as it should.
Your boiler has stopped running because an external safety thermostat has detected that the water temperature has become too hot.
Your boiler is still working but cannot reach its full power, meaning your radiators might not get as hot as they should.
Your boiler has shut down because the water returning from your radiators has become too hot, usually caused by a circulation problem.
Your boiler has lost its wireless connection with your thermostat or remote control, meaning they can no longer talk to each other to manage your heating.
Your boiler's water circulation pump has stopped working, which means the system cannot move hot water to your radiators or taps.
Your boiler is struggling because there is trapped air inside the system, which is preventing hot water from circulating properly to your radiators.
Your boiler has detected a problem with the sensor that monitors water temperature as it returns from your heating system, causing the unit to stop running for safety.
Your boiler has stopped running because it senses that even though the burner is lit, the water inside isn't getting any warmer.
Your boiler is struggling to accurately measure the temperature of the water inside it, so it has shut down to prevent overheating.
Your boiler is having trouble measuring water temperatures, so it has stopped working to prevent any damage to the internal system.
Your boiler has detected that the exhaust gases are getting too hot and has safely shut itself down to prevent damage.
Your boiler has detected that the flame inside has gone out unexpectedly or failed to light, so it has safely shut down to prevent gas from building up.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes