32 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has lost the ability to accurately measure the temperature of the water returning to it, so it has safely shut down to prevent overheating.
Your boiler is struggling to accurately measure the temperature of your hot water, which may cause your taps to run cold or the water temperature to fluctuate.
Your boiler has detected that it is not sensing water correctly within the system, causing it to stop running to prevent potential damage.
Your boiler is failing to light the fuel inside the unit because it cannot detect a flame, causing it to stop operating for safety reasons.
Your boiler is failing to start because the electrical supply wires—specifically the live and neutral—have been connected the wrong way around.
Your boiler has detected that it is firing without enough water inside, or a temperature sensor has failed, causing it to shut down to prevent overheating.
Your boiler is struggling to detect a flame, which means it cannot stay lit to provide heating or hot water.
Your boiler has detected that the electrical supply wires are connected in the wrong order, which is preventing it from starting up safely.
Your boiler has detected an issue with the flame during operation, causing it to shut down for safety reasons.
Your boiler is failing to start because the electrical supply wires are connected in the wrong order.
Your boiler has stopped working because it has detected a specific internal problem, which it will show by alternating the 'F' with another number or letter.
Your boiler has stopped working because a sensor that measures the water temperature is not sending a proper signal to the control system.
Your boiler's internal sensor that monitors the water temperature returning to the unit is malfunctioning, which is causing the system to stop working as a safety precaution.
Your boiler is struggling to accurately detect the temperature of your hot water, which means it may fail to provide a consistent supply or stop heating your water altogether.
Your boiler has detected that it is running without enough water inside, which prevents it from heating safely.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler's internal computer is experiencing a communication fault and cannot control the system correctly.
Your boiler has detected an issue with the flame during operation and has safely shut itself down to prevent any risk.
Your boiler has detected an internal communication error between its main components and requires a professional diagnostic check to identify the faulty link.
Your boiler has detected that it is getting dangerously hot and has shut itself down to prevent damage.
Your boiler has detected that it is running much hotter than it should be and has shut itself down to prevent any internal damage.
Your boiler has stopped heating your radiators and water because the internal water pressure has dropped too low.
Your boiler has detected that the internal mechanism responsible for clearing waste gases is not spinning correctly, so it has safely shut down to prevent any unsafe operation.
Your boiler has detected that it is running much hotter than it should be and has switched itself off to prevent internal damage.
Your boiler's main control computer is experiencing a communication error and cannot operate safely.
Your boiler has failed to light the flame or keep it running, so it has safely shut itself off to prevent gas build-up.
Your boiler has switched itself off for safety and is displaying a 'lockout' status, which will be accompanied by a second flashing code to tell you exactly what is wrong.
Your boiler has tried to start three times but cannot ignite, meaning you currently have no heating or hot water.
Your boiler has detected that it is becoming dangerously hot and has shut itself down to prevent any internal damage.
Your boiler has shut down because it has reached an unsafe temperature, essentially tripping a safety switch to prevent damage.
Your boiler is failing to light the flame properly after three attempts, meaning it currently cannot provide heating or hot water.
Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage.
BoilerFaultCodes