18 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has shut down because a safety sensor has detected that it is getting far too hot, likely due to a blockage or a pump failure.
Your boiler is failing to light the gas even though it is trying to, which prevents your heating and hot water from working.
Your boiler thinks a flame is burning even though it hasn't actually sparked or started, causing it to shut down for safety.
Your boiler is still detecting a flame even though it has tried to shut off the gas supply, which is a safety conflict.
Your boiler is struggling to accurately measure the temperature of your stored hot water, so it has safely stopped heating the tank to prevent overheating.
Your boiler has detected an issue with the sensor that monitors internal water pressure, meaning it cannot confirm if there is enough water to operate safely.
Your boiler has detected a problem with how it tracks its own flame, causing it to shut down for safety purposes.
Your boiler has stopped working because the flame inside went out while it was trying to heat your water or home.
Your boiler's computer memory chip is not being recognised or is mismatched, which prevents the system from starting up.
Your boiler is struggling to stay lit when it is running at its lowest power level, often causing it to shut down for safety.
Your boiler has tried to start up but cannot detect a flame, meaning it cannot provide heating or hot water.
Your boiler has detected that the sensors monitoring its internal temperature are giving incorrect readings or have failed, causing the system to shut down for safety.
Your boiler is struggling to pump water through its internal system effectively, which is likely preventing it from producing heat or hot water.
Your boiler has sensed that the water inside is getting much hotter than it should be and has shut down as a safety precaution.
Your boiler is overheating too quickly because water isn't moving through the system fast enough.
Your boiler has detected that the water temperature is fluctuating unevenly inside the unit, forcing it to shut down to prevent damage.
Your boiler has detected that the water pressure in your heating system is falling much faster than normal, which usually indicates a significant leak or a fault with the pressure sensor.
Your boiler has detected that the water pressure in the system has dropped below the minimum level required to operate safely.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes