20 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Genus ONE
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Your boiler has stopped working because it cannot light its internal flame to heat your water.
Your boiler has detected that the water inside it has become dangerously hot and has shut itself down to prevent damage or safety risks.
Your boiler has detected that water is not flowing through the system correctly, which is preventing it from heating your home safely.
Your boiler has detected that hot water isn't moving around your radiators or pipes properly, causing it to shut down to prevent damage from overheating.
Your boiler has detected that the internal fan responsible for safely removing exhaust gases is not spinning correctly, so it has shut itself down to keep your home safe.
The internal computer in your boiler is experiencing a communication error or software glitch, preventing it from managing your heating and hot water correctly.
Your boiler has stopped working because it has lost the electronic signal from the sensor that monitors the temperature of the water leaving the unit.
Your boiler has stopped working because a sensor that measures the temperature of the water leaving the boiler is sending an incorrect electrical signal.
Your boiler has detected that an external safety sensor, typically linked to your underfloor heating system, has triggered, causing the system to stop working to prevent overheating.
Your boiler has detected a flame signal when it is not supposed to be burning, which is a safety mechanism preventing it from starting.
Your boiler's internal computer has encountered a software internal error and is unable to safely manage the heating process.
Your boiler is struggling to accurately measure the temperature of the water flowing through your system because it has lost communication with its internal thermometers.
Your boiler has failed to start multiple times and has automatically locked itself for safety to prevent a gas buildup.
Your boiler failed to light on its first attempt, meaning it is currently unable to produce heat or hot water.
Your boiler is currently unable to sense the temperature of your hot water properly, which means it will stop providing hot water until the faulty sensor is fixed.
Your boiler is struggling to detect the temperature of the water it is trying to heat for your taps and shower, so it has stopped producing hot water to prevent overheating.
Your boiler is struggling to detect the temperature of your hot water cylinder, which means it may fail to provide hot water or heat it correctly.
Your boiler is struggling to accurately read the temperature of your hot water cylinder because there is an electrical fault with the sensor cable or the connection.
Your boiler has detected that the water inside its internal storage tank is reaching dangerously high temperatures and has shut itself down to prevent damage or safety risks.
Your boiler’s remote wall controller is having trouble communicating its temperature reading to the heating system.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes