26 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has shut down because it detected that exhaust fumes are not escaping correctly through the chimney, which is a critical safety issue.
Your boiler has stopped working because the water pressure inside the system has dropped too low and needs to be topped up.
Your boiler has too much water pressure inside the system and needs some water removed to work safely.
Your boiler's temperature sensor for hot water has stopped working properly, which means you might not get any hot water or it may be inconsistent.
Your boiler has detected a problem with the temperature sensor that monitors the water being sent to your taps and radiators, causing the system to stop working for safety.
Your boiler has failed to light the flame, which means you will not have any heating or hot water until it is reset or repaired.
Your boiler has shut down because it has detected it is getting too hot, which is usually caused by air trapped in the system or a circulation problem.
Your boiler is struggling to detect a flame, which prevents it from firing up to provide heating or hot water.
Your boiler has detected that water is not moving through the system properly, which is preventing it from heating up safely.
Your boiler has detected an issue with an internal sensor used for specific system configurations, which is preventing it from running correctly.
Your boiler has detected an internal electrical fault with the part that controls the gas flow, meaning it cannot safely ignite or regulate the flame.
Your boiler's computer has been set up with the wrong internal configuration settings, meaning it doesn't know which type of ventilation system it is using.
Your boiler has detected that the exhaust gases are too hot or the sensor that monitors them has failed, causing the system to shut down for safety.
Your boiler has detected an issue with the sensor that monitors exhaust gases, and it has shut down for safety purposes.
Your boiler has detected a communication problem with its internal fan, which means it cannot safely clear waste gases and will not fire up.
Your boiler has stopped working because water is backing up inside the system, likely due to a blocked or frozen external drainage pipe.
Your boiler has been manually reset too many times in a short period and has temporarily locked itself for safety.
Your boiler has detected that the electricity supply coming into your home is too weak for it to operate safely, causing the system to shut down.
Your boiler has detected an issue with the electrical power supply frequency coming into your home and has shut down as a safety precaution.
Your boiler is repeatedly failing to keep a flame lit, meaning it cannot provide heating or hot water for your home.
Your boiler has detected that one of the control buttons on the front panel is stuck or faulty, preventing you from changing settings.
Your boiler has lost its connection with the smart thermostat or remote control system, meaning they can no longer talk to each other to manage your heating.
Your boiler has detected that a temperature sensor is loose or isn't measuring the heat of the water correctly as it leaves the unit.
Your boiler has detected an issue with the air or gas mixture during ignition, causing it to lock itself out for safety.
Your boiler is struggling to burn gas correctly and is failing to maintain a steady flame, often due to air in the system or a dirty internal sensor.
Your boiler has shut down because it cannot safely expel exhaust fumes out of the external flue pipe.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes