10 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler is failing to light the flame needed to produce heat or hot water, meaning it has safely shut itself down to prevent a gas buildup.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent any damage or safety issues.
Your boiler is struggling to detect the temperature of the water being heated for your taps, which means it has stopped producing hot water to prevent internal overheating.
Your boiler has detected that the water temperature is not rising as expected, likely because of a faulty sensor or a problem with water flowing through the system.
Your boiler has detected an issue with the internal air circulation fan, which is preventing it from safely lighting and operating.
Your boiler has stopped working because it cannot detect enough water pressure inside the system to operate safely.
Your boiler has detected that the temperature of the gases leaving your flue is abnormal, so it has stopped working for your safety.
Your boiler has detected that the temperature in the exhaust pipe is not what it expects, so it has safely shut itself down to prevent overheating.
Your boiler has stopped working because it cannot light or stay lit, meaning it is currently unable to provide heating or hot water.
Your boiler has stopped working because the internal water pressure has dropped too low to operate safely.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes