39 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Main Eco Compact
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
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Your boiler has detected a problem with a internal sensor that monitors water temperature, meaning it cannot safely heat your home or water.
Your boiler is failing to clear its system of air before starting, so it has safely shut down to prevent ignition.
Your boiler is failing to light the fuel inside even though it is trying to start, so it has safely shut itself down to prevent a gas build-up.
Your boiler's internal computer has crashed or is struggling to process the reset command, preventing it from starting up again safely.
Your boiler is lighting up but shutting off shortly after because it cannot confirm that the flame is staying on, meaning you currently have no heating or hot water.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.
Your boiler is failing to light properly or stay lit, meaning your heating and hot water will not work until it is reset or repaired.
Your boiler has reached an unsafe temperature or detected excessive heat in the exhaust, causing it to shut down for safety.
Your boiler has stopped working because water is not circulating correctly through the system to prevent it from overheating.
Your boiler has detected an issue with how it clears exhaust gases, which has caused the system to shut down for safety.
Your boiler is currently warming itself up in the background to ensure you have hot water ready and available when you turn on a tap.
Your boiler is struggling to detect the temperature of the water coming from your taps, which means it cannot reliably provide hot water.
Your boiler has detected that it is overheating and has automatically switched itself off to prevent damage.
Your boiler is struggling to clear exhaust gases safely, so it has stopped working to prevent any potential build-up of fumes.
Your boiler is struggling to circulate water properly, likely because the pressure inside your heating system has dropped too low or the internal pump is stuck.
Your boiler is struggling to detect the temperature of the water for your taps, which means it cannot reliably provide hot water.
Your boiler has lost its ability to measure the temperature of the water being sent to your radiators, so it has shut down as a precaution to prevent overheating.
Your boiler is having trouble measuring the temperature of your hot water, which likely means your taps and shower are running cold.
Your boiler's internal thermometer for the heating system has stopped working correctly, so it has shut down to prevent itself from overheating.
Your boiler has encountered a problem specifically with the central heating operation, meaning your radiators likely won't heat up even though your hot water might still work.
Your boiler is providing central heating as normal, but there is a specific problem preventing its ability to heat your water.
Your boiler thinks a hot water tap is turned on even when all taps are closed, which prevents the heating from working correctly.
Your boiler is not detecting that you have turned on your hot water tap, meaning the water will likely stay cold.
Your boiler has detected that it is firing without enough water inside, which has triggered a safety shutdown to prevent internal damage.
Your boiler has stopped working because the internal fan, which safely exhausts fumes, isn't spinning correctly or communicating with the control board.
Your boiler has detected that the internal fan, which safely removes waste gases, is not spinning correctly or at all.
Your boiler has failed to ignite the gas burner, which means it cannot heat your water or radiators.
Your boiler has identified a problem with the sensor that monitors the temperature of the water leaving the unit, causing it to shut down for safety.
Your boiler has failed to light several times and has locked itself for safety, meaning you currently have no heating or hot water.
Your boiler has detected that the electrical supply wires are connected in the wrong order, causing the system to lock out for safety.
Your boiler is not receiving enough electricity from the mains supply to operate safely and effectively.
Your boiler has reached an unsafe temperature and has automatically shut down to prevent damage.
Your boiler has too much water inside it, causing the pressure to rise to a level where the safety valve must release the excess to prevent damage.
Your boiler has lost water pressure, meaning there isn't enough water in the system to keep the heating and hot water running.
Your boiler has attempted to light the gas burner multiple times but has failed to detect a flame, causing it to shut down for safety reasons.
Your boiler has detected an issue with the sensor that monitors the temperature of the water returning to the unit, causing it to stop running as a safety precaution.
Your boiler is simply indicating that it is currently heating up water for your taps.
Your boiler is currently operating normally and providing heat to your radiators.
Your boiler is receiving electrical power and is currently switched on and ready to operate.
BoilerFaultCodes