18 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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 lost the ability to accurately measure the water temperature, so it has safely shut itself down to prevent overheating.
Your boiler has detected that it is getting too hot and has automatically shut down to prevent damage or dangerous overheating.
Your boiler has stopped working because it is unable to accurately measure the temperature of the water returning to it, so it has shut down as a precaution.
Your boiler has stopped working because a sensor that monitors the water temperature inside your heating system is giving incorrect or no information to the control board.
Your boiler has failed to light the gas flame required to provide heating or hot water.
Your boiler has automatically shut itself down because it detected that the internal water temperature has become dangerously high.
Your boiler has detected that hot exhaust gases are not escaping properly and has shut itself down as a safety precaution.
Your boiler has switched off because the water level inside your central heating system has dropped too low to operate safely.
Your boiler has lost the ability to accurately measure the temperature of the water being sent to your radiators, so it has shut down to prevent overheating.
Your boiler is currently unable to read the temperature of the water returning to it from your radiators, so it has shut down to prevent damage.
Your boiler has stopped working because the amount of water pressure in your heating system has dropped too low to operate safely.
Your boiler has detected that the water leaving the unit is significantly hotter than the water returning, suggesting a possible blockage or a pump that isn't moving water efficiently.
Your boiler has stopped working because the mechanical fan responsible for pushing out exhaust gases is failing to reach the necessary speed.
Your boiler's computer system has detected a configuration error and has safely shut down to prevent incorrect operation.
Your boiler is struggling to talk to your room thermostat or remote controller, meaning it doesn't know when to switch your heating on or off.
Your boiler has detected a flame inside when there shouldn't be one, which forces the system to shut down for safety reasons.
Your boiler is operating normally and the burner is currently lit, which is exactly what should be happening when it is heating your water or home.
Your boiler has lost its power connection, meaning it cannot start up or provide any heating and hot water.
BoilerFaultCodes