33 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's internal fan is failing to start or power up, which means the unit cannot safely clear exhaust gases and will refuse to ignite.
Your boiler is having trouble reading the temperature outside, which means it might not adjust your heating correctly as the weather changes.
Your boiler's computer brain is having trouble processing information from its internal sensors and has shut down for safety.
Your boiler has detected a problem with the sensor that monitors your hot water, so it has shut down that function to prevent overheating.
Your heater is temporarily pausing while it carries out a routine internal calibration check to ensure the fan is running at the correct speed.
Your boiler is failing to ignite, meaning it cannot create the flame needed to provide heating and hot water.
Your boiler has tried to light several times but has been unable to create a flame, meaning you will not have any heating or hot water.
Your boiler has shut down because it has detected it is getting too hot, which is a safety feature to prevent damage.
Your boiler's computer memory has encountered a software error and can no longer process instructions safely.
Your boiler has detected a problem with the sensor that monitors the safety of the exhaust gases and has shut down to prevent overheating.
Your boiler has been manually reset too many times in a short window, causing the system to lock itself out for safety.
Your boiler has stopped working because it has been manually reset too many times in a short window, suggesting an underlying fault that needs professional attention.
Your boiler has stopped working because the water pressure in the central heating system has dropped too low.
Your boiler has detected that the water pressure in the central heating system is too low or too high for it to operate safely.
Your boiler has detected a flame when there shouldn't be one, causing it to shut down for safety.
Your boiler has detected a problem with the fan that clears exhaust gases, preventing the unit from starting up for safety reasons.
Your boiler is failing to detect the flame needed to heat your home, causing the system to shut down for safety.
Your boiler's temperature sensor is reporting an error, which means the system cannot accurately track how hot the water is and has stopped running as a safety precaution.
Your boiler has detected that the temperature sensors are giving inconsistent readings, which usually happens because the water isn't flowing correctly or the system is low on pressure.
Your boiler has shut itself down as a safety precaution because it detected that the exhaust gases are becoming too hot.
Your boiler's hot water sensor is not reading the temperature correctly, which means you may have inconsistent or no hot water.
Your boiler has failed to light after several attempts and has locked itself for safety, leaving you without heating.
Your boiler is not receiving the correct amount of electricity from your home's power supply to run safely and has shut down as a precaution.
Your boiler has detected that there is not enough water in the system to operate safely and effectively, causing it to shut down.
Your boiler is successfully heating your radiators, but it is failing to send heat to your hot water tank.
Your boiler has lost all power, meaning it cannot operate and the control screen has gone completely blank.
Your boiler has switched itself off because it became too hot, acting as a safety measure to protect the internal components.
Your heater has encountered a temporary electronic error and needs a manual reboot to resume operation.
Your boiler has detected an issue with the sensor that monitors the temperature of the water returning to the unit, causing it to shut down to prevent damage.
Your boiler has stopped running because it cannot detect a change in water temperature, causing it to shut down for safety.
Your boiler has detected a communication problem with the gas valve, which means it cannot safely ignite to provide heating or hot water.
Your boiler has detected that the water pressure is either too low or the sensor that monitors it has stopped working.
Your boiler has too much water in the system, which can put unnecessary stress on the internal seals and pipework.
BoilerFaultCodes