12 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 →
Tap any card for details
Your boiler's internal thermometer is failing to send reliable signals, so the system has shut down to prevent it from overheating.
Your boiler has detected that it is getting too hot and has automatically shut down to prevent any damage or safety hazards.
Your boiler has stopped working because it failed to ignite the gas burner, meaning you will currently have no heating or hot water.
Your boiler has failed to light the flame needed to heat your water and radiators.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.
Your boiler has detected an issue with the airflow or ventilation system, and for safety reasons, it has turned itself off to prevent harmful gases from escaping.
Your boiler has lost the ability to accurately measure its own water temperature, so it has safely shut down to prevent overheating.
Your boiler is struggling to accurately measure the temperature of the hot water it produces, so it has turned off the hot water supply to prevent overheating.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler has stopped working because the internal component responsible for pushing exhaust gases out of the flue is not operating correctly.
Your boiler is struggling because it detects a temperature difference between the water leaving and returning that should not be there, causing it to shut down for safety.
Your boiler has lost its connection with the digital thermostat or timer controller, meaning it cannot receive instructions to heat your home or water.
BoilerFaultCodes