27 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has been automatically shut down because an external safety device, such as a frost thermostat or a heat link, has triggered a signal to stop the system.
Your boiler has paused the heating because it cannot move water through your radiators fast enough, likely due to a blockage or closed valves.
Your boiler has detected that the water is not flowing or heating correctly while producing hot water, causing it to pause the hot water function to protect itself.
Your boiler’s internal computer settings have been incorrectly adjusted, which is preventing it from knowing how much power it should use to operate safely.
Your boiler has detected an unusual temperature difference while it is supposed to be switched off, so it is temporarily pausing to prevent any potential issues.
Your boiler has automatically stopped heating because the exhaust gases getting rid of your smoke and fumes are currently too hot.
Your boiler has stopped working because it cannot detect a vital safety sensor that monitors the temperature of the gases leaving your home.
Your boiler has detected an electrical fault in a sensor that monitors exhaust gases and has safely shut down to prevent incorrect operation.
Your boiler is currently running a self-cleaning air-removal cycle because it cannot detect water moving through the system properly.
Last predecessing error
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Last predecessing error
Last predecessing error
Your boiler is failing to light the internal flame properly, meaning it cannot produce heat or hot water.
Your boiler has detected an electrical fault in its internal control circuit, which has caused it to shut down to prevent further damage.
Your boiler is failing to light the internal burner, which means it cannot produce any heat or hot water.
Your boiler has lost its electrical connection or is struggling to process the power supply, causing it to shut down for protection.
Your boiler is struggling to accurately adjust its internal settings, which means it has paused operation to prevent any potential damage.
Your boiler has stopped working because an internal electrical safety fuse has blown, preventing the system from powering up safely.
Your boiler has detected that the water inside the system has become dangerously hot and has shut itself down to prevent damage.
Your boiler has detected that the water returning to it from your radiators is getting too hot, so it has shut down to prevent damage.
Your boiler has stopped working because it cannot detect that the internal fan is spinning, which is necessary for safe operation.
Your boiler's electronic control panel is not receiving power or is failing to communicate, meaning the boiler has completely shut down and cannot be operated.
Your boiler has detected that the gases venting out of your flue are getting dangerously hot and has shut itself down to prevent damage or overheating.
Your boiler has lost water pressure and needs to be topped up to work at full capacity again.
Your boiler has too much water inside the system, causing the pressure to rise above the safe limit.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes