62 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 is simply reminding you that it is due for its annual safety check and professional service.
Your boiler is struggling to light or detect a steady flame, which means it has shut down as a safety precaution.
Your boiler is struggling to light or detect a flame, which means it has stopped providing heating and hot water for safety.
Your boiler is currently running at its highest power setting for a professional combustion test and should return to normal operation automatically after a short period.
Your boiler is currently running a manual test mode to check the flue and emissions, and it's not actually broken.
Your boiler has failed to light the flame, which means it has shut down for safety to prevent gas from flowing without being burned.
Your boiler has failed to light the flame and has locked itself for safety, leaving you without heating or hot water.
Your boiler has got too hot and has automatically shut down for safety to prevent internal damage.
Your boiler has shut itself down because it detected that the internal water temperature has become too hot.
Your boiler has shut down because it detected that the exhaust gases are getting too hot or a safety fuse has blown to prevent overheating.
Your boiler has stopped working safely due to a general lockout, which means the system has detected an error and shut itself down as a precaution.
Your boiler has detected that there is not enough water pressure or flow to operate safely and has stopped working as a result.
Your boiler has stopped working because the water pressure is too low for it to run safely.
Your boiler has stopped working because the fan that helps remove waste gases is not spinning at the correct speed or communicating properly with the control board.
Your boiler has detected a problem with the fan that clears away waste gases, causing the system to shut down for safety.
Your boiler's internal sensor that monitors the temperature of the water for your radiators has developed a fault, meaning the system cannot heat your home safely.
Your boiler is struggling to accurately measure its own temperature, meaning your central heating may not heat up reliably or could cut out entirely.
Your boiler has detected a problem with the sensor that monitors the water temperature returning from your radiators, causing the system to stop working for safety.
Your boiler is struggling to accurately measure the temperature of the water coming out of your hot taps, which usually means your hot water won't reach the right temperature or may not work at all.
Your boiler is having trouble reading the temperature outside, which may cause your heating to respond incorrectly to weather changes.
Your boiler has lost connection with its outdoor temperature sensor, which helps it adjust the heating based on the weather.
Your boiler has detected that a temperature sensor in the flue has stopped working correctly, which has caused the system to shut down for safety.
Your boiler has detected an issue with the sensor that monitors the temperature of the exhaust fumes, causing the system to shut down for safety.
Your boiler has shut down because a sensor detected that the exhaust gases are becoming too hot, which is a safety measure to prevent damage to the internal components.
Your boiler has shut down because a sensor in the exhaust pipe has detected that the flue gases are getting too hot.
Your boiler detects a flame when there shouldn't be one, so it has shut down as a safety precaution.
Your boiler is struggling to detect a flame, which means it cannot fire up to provide heating or hot water.
Your boiler has detected that a sensor responsible for monitoring the temperature of the water returning from your radiators has developed a fault, preventing the system from operating correctly.
Your boiler has detected a problem with the sensor that monitors the temperature of the water returning to the unit, causing it to shut down for safety.
Your boiler is overheating because the water is not circulating quickly enough between the internal pipes.
Your boiler has detected that the water is heating up too quickly or not circulating properly, causing it to shut down to prevent overheating.
Your boiler has stopped working because the water isn't moving through the system properly, causing it to overheat.
Your boiler has detected that water is heating up too quickly because it isn't moving through the system properly.
Your boiler has overheated because water is not circulating properly through the system.
Your boiler is having trouble measuring the temperature of the cold water coming in, which may affect how well it heats your hot water.
Your boiler is struggling to accurately measure the temperature of the water entering the system, which can cause inconsistent hot water temperatures.
Your boiler has stopped working because it cannot safely detect or ignite a flame, resulting in a total lockout for safety reasons.
Your boiler has shut down because it cannot safely detect or control the gas supply needed to light the flame.
Your boiler has stopped working because it failed to ignite or check the gas flow properly for safety reasons.
Your boiler has failed to ignite and has locked itself out for safety, meaning you will have no heating or hot water until it is reset or repaired.
Your boiler's internal computer has lost its settings and needs to be told which specific model it is before it can operate.
Your boiler has stopped working because the internal gas valve system has failed to operate correctly, causing the unit to shut down for safety.
Your boiler has stopped working because it cannot safely ignite the gas or maintain a flame.
Your boiler has stopped working because it cannot safely detect or control the gas supply, causing it to lock itself for safety.
Your boiler has shut down because it detected it was getting too hot too quickly while trying to start up.
Your boiler has failed to ignite properly or safely maintain a flame, causing it to shut down for your protection.
Your boiler is struggling to detect a flame after it starts, causing the system to shut down for safety.
Your boiler has detected an unsafe flame or burning pattern and has shut itself down to prevent damage or dangerous fumes.
Your boiler has sensed a flame when there shouldn't be one, or the signal that proves a flame is burning safely has failed.
Your boiler is struggling because the electrical power being fed to it is unstable or at the wrong voltage level.
Your boiler is having trouble controlling the flame brightness, which usually means the internal gas control system has stopped working correctly to keep you safe.
Your boiler has lost its connection to the thermostat or controller that manages the second heating zone in your home.
Your boiler has stopped working because it has detected a problem with its internal electrical connections or wiring.
Your boiler has detected an internal electrical communication problem or a wiring mistake that is preventing it from starting up safely.
Your boiler is having trouble communicating with the solar panel control system, which means your renewable energy setup isn't working correctly with your heating.
Your boiler's internal computer has lost its settings and doesn't know which model it is supposed to be operating as.
Your boiler’s internal computer has forgotten its settings and does not know which model it is supposed to be, causing it to stop working entirely.
Your boiler’s internal computer has forgotten which model it is, meaning it has lost its configuration settings and cannot operate.
Your boiler is currently running a maintenance test mode used by engineers to check emission levels at low power.
Your boiler has shut down because it is getting too hot while trying to provide hot water.
Your boiler is currently running in a specialist service mode used by engineers to test the system at its lowest power setting.
Your boiler is simply reminding you that its annual service is due and it needs a routine checkup by a professional.
BoilerFaultCodes