50 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Keston System 30
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Your boiler's electronic identity card is missing or has failed, meaning the system cannot confirm its specific model settings to start up.
Your boiler's internal memory chip has developed a communication problem or has failed, preventing the control board from recognizing the unit's settings.
Your boiler thinks it can see a flame even though it hasn't tried to light yet, which is causing it to shut down for safety.
Your boiler has tried to light several times without success, meaning your heating and hot water will not work until the gas supply is restored or the ignition is fixed.
Your boiler thinks it sees a flame even though it hasn't finished its start-up sequence, which prevents it from firing up safely.
Your boiler has become too hot and has shut down as a safety precaution to prevent damage.
Your boiler has been turned off and on again while it was already trying to report a different fault, causing it to become stuck.
Your boiler has detected that the internal fan, which safely clears exhaust gases, has stopped spinning correctly, causing the system to shut down for safety.
Your boiler has shut down because it detected that the exhaust gases are getting too hot, which can indicate poor water circulation or a problem with the main heat exchanger.
Your boiler is failing to detect the flame it has lit, which is preventing it from running safely.
Your boiler has detected an internal electrical problem with the mechanism that controls the gas supply, meaning it cannot safely light itself to provide heating or hot water.
Your boiler’s internal computer has encountered a critical electronic failure and can no longer control the heating system safely.
Your boiler has detected that its internal temperature sensors are giving conflicting readings and cannot confirm if they are measuring the correct pipes.
Your boiler's internal computer has detected a technical software or hardware failure and can no longer manage the heating system safely.
Your boiler has detected that the water inside is getting too hot because it isn't moving through the system properly.
Your boiler has switched itself off because the water returning to it is too hot, which usually means the water isn't moving through your radiators properly.
Your boiler is struggling to detect or maintain the correct amount of water inside the system.
Your boiler has shut down because it keeps losing water pressure and needs a manual reset and top-up.
Your boiler's main internal computer has detected a serious internal error and has stopped working to protect the system.
Your boiler has started an ignition sequence but the flame went out, likely due to a blocked pipe or an issue with the gas supply.
Your boiler has detected an electrical fault with the internal sensor that monitors water temperature, causing the system to shut down for safety.
Your boiler has lost communication with its internal temperature monitoring system, meaning it cannot safely tell how hot the water is and has shut down as a precaution.
Your boiler has detected a fault with the sensor that monitors hot water temperature, meaning it cannot safely heat water for your taps.
Your boiler has detected an electrical fault with the sensor that manages your hot water temperature.
Your boiler has detected that the electrical power coming from your mains supply is too low for it to operate safely.
Your boiler has detected an issue with the electrical power coming into your home, meaning the electricity speed doesn't match what the boiler needs to run safely.
Your boiler has lost communication with its internal temperature sensor, preventing it from heating your home or water safely.
Your boiler has detected that the water pressure is too low to operate safely and has shut down to protect itself.
Your boiler’s control panel has developed a technical fault that is preventing the reset button from working properly.
Your boiler has too much water inside its system, which is causing it to shut down for safety.
Your boiler's internal display screen and main control computer are struggling to talk to each other, which prevents the boiler from starting.
Your boiler's internal thermometer that measures the temperature of the water coming back into the unit has developed an electrical fault, causing the system to stop working for safety.
Your boiler has lost signal from the pipe that monitors water returning from your radiators, meaning it cannot safely regulate the heating temperature.
Your boiler has detected a technical fault with the sensor that monitors exhaust gases, causing the system to shut down for safety.
Your boiler's main control panel has lost connection with its internal computer, meaning instructions are not being sent or received correctly.
Your boiler has detected an electrical fault with the sensor that monitors exhaust gases, causing the system to shut down for safety.
Your boiler has encountered a critical system error that has forced it to shut down to prevent damage or unsafe operation.
Your boiler's internal computer chip is missing or not communicating properly with the main control board, preventing the system from starting.
Your boiler has detected that there is not enough water in the system to operate safely, which has caused it to shut down.
Your boiler has lit correctly but the flame has gone out unexpectedly, causing the system to shut down for safety.
Your boiler has detected an issue with the fan, meaning it cannot safely clear exhaust fumes and will not start for your safety.
Your boiler has sensed that water is not circulating correctly or a temperature sensor has failed, causing the system to shut down for safety.
Your boiler has detected a problem with the sensor that monitors the temperature of the water returning from your radiators, preventing it from heating correctly.
Your boiler has lost communication with the sensor that measures the temperature outside, which may cause your heating to be less efficient or run at the wrong temperature.
Your boiler is not receiving enough electrical power from the mains supply to operate safely.
Your boiler's internal computer has encountered a critical error and can no longer control the heating system safely.
Your boiler has shut down because the water inside the unit has become too hot, likely due to a circulation problem.
Your boiler is failing to keep a steady flame, causing the system to shut down for safety purposes.
Your boiler has been manually reset too many times in a short period and has locked itself out as a safety precaution.
Your boiler thinks it sees a flame even though it hasn't finished its start-up sequence, so it has locked itself out for safety.
BoilerFaultCodes