53 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler's electronic control board has not completed its necessary setup process or is failing to recognize its internal settings.
Your boiler's internal electronic brains have stopped talking to each other, which means the system cannot operate or provide heat.
Your boiler has tried to light several times and failed, so it has locked itself out to prevent further wasted gas.
Your boiler detects a flame inside the system even when it hasn't been told to ignite, which is a safety concern that prevents it from starting up.
Your boiler has tried to ignite several times but the flame keeps going out, causing the system to shut down for safety.
Your boiler's internal computer components have lost the ability to speak to each other properly, meaning the system cannot operate.
Your boiler is struggling to detect a flame when it tries to start up, which prevents the system from running safely.
Your boiler has detected an electrical issue during the ignition process, meaning it cannot safely confirm a flame is present and has locked out for safety.
Your boiler has switched itself off because it has detected that the internal water temperature has become too hot.
Your boiler has detected a safety-related issue with the internal component that regulates gas flow, preventing the system from firing up.
Your boiler has stopped working because the fan that safely clears exhaust gases isn't running at the correct speed.
Your boiler has stopped working because the fan that removes exhaust gases is stuck or has failed, meaning the system cannot run safely.
Your boiler has detected that the fan responsible for clearing exhaust gases is not spinning correctly or is stuck.
The fan that moves air through your boiler has stopped spinning or is damaged, which means the boiler cannot safely operate and has shut down.
Your boiler has detected a blockage or a problem with the air pipe that vents exhaust gases outside, causing the system to stop for safety.
Your boiler has detected that smoke and exhaust gases are not being cleared away safely through the flue pipe, causing it to shut down to prevent a build-up of fumes.
Your boiler has detected that waste gases are not leaving the flue pipe properly, which has caused the system to shut down for your safety.
Your boiler is struggling to maintain a steady flame at low heat levels and has shut down for safety.
Your boiler has shut down because it detected that the gas is not burning correctly when running at full capacity.
Your boiler has detected an unusual flame signal, which means it cannot safely confirm if the gas is burning correctly and has shut down as a precaution.
Your boiler has detected that there is not enough water in the system to operate safely, causing it to shut down temporarily.
Your boiler has detected that the water pressure in the system is too low to operate safely.
Your boiler has detected that the water pressure is too low to operate safely, or the sensor that monitors the water level is faulty.
Your boiler has detected a blockage or restriction in the flue pipe that expels exhaust fumes, causing it to shut down for safety.
Your boiler has detected a blockage or a fault in the flue system that is preventing exhaust fumes from escaping safely at high power.
Your boiler's main internal computer has detected a significant electronic failure that is preventing the system from running safely.
Your boiler's computer has lost contact with the fan, which means it cannot blow waste gases out of the flue and has switched itself off for safety.
Your boiler’s internal computer brains are unable to talk to each other, causing the system to shut down for safety.
Your boiler is struggling to accurately measure the temperature of your hot water, which means it has stopped heating it to prevent the system from overheating.
Your boiler has encountered an internal electronic communication error between the control boards, meaning it cannot safely regulate the burner.
Your boiler's central heating sensor has detected an issue, meaning the system cannot accurately monitor the water temperature for your radiators.
Your boiler has sensed that the water inside is becoming too hot and has shut down as a safety precaution to prevent damage.
Your boiler has shut down because there is a wide temperature difference between the water leaving the boiler and the water returning to it, usually caused by poor circulation.
Your boiler is struggling to control the flow of gas or water correctly, suggesting a mechanical part inside is stuck or has moved further than it should.
Your boiler has lost its connection with a temperature control sensor, meaning it cannot safely determine how hot the water is in certain parts of the system.
Your boiler has detected a problem with the sensor that monitors the temperature of the water returning from your radiators, preventing it from heating your home correctly.
Your boiler has detected that the water returning from your radiators is too hot, causing it to shut down to prevent damage.
Your boiler has detected that the water is heating up or cooling down at an unusual rate, suggesting a potential circulation problem.
Your boiler has detected an internal communication failure between its electronic control boards and cannot operate safely.
Your boiler has detected an issue with the sensor that monitors exhaust fumes, causing the system to shut down for safety.
Your boiler has failed its internal self-checking process and cannot automatically set the correct gas-to-air mixture required to run.
Your boiler has tried and failed to automatically adjust its internal settings too many times and has now locked itself out for safety.
Your boiler has detected that the air and gas mixture used for burning is not balanced correctly, causing the system to shut down for safety.
Your boiler has failed its internal self-tuning process and cannot set itself up correctly to run safely.
Your boiler has shut down because it cannot correctly balance the mixture of gas and air required for a clean and safe burn.
Your boiler has failed an internal safety check during startup and has locked itself down as a precaution.
Your boiler has failed its automatic gas calibration process, which means it cannot safely regulate the gas and air mixture required to stay alight.
Your boiler has been reset too many times in a short period and has now locked itself out as a safety precaution.
Your boiler has detected that the water pressure in your central heating system is too low to operate safely.
The internal software components of your boiler are unable to communicate because they are running mismatched versions.
Your boiler's computer has encountered a software error that has caused it to lock down for safety.
Your boiler's internal electronic timer has failed, which means the system cannot automatically manage its heating schedule.
Your boiler is displaying a maintenance reminder indicating that a routine professional service is now due to keep the system running safely.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes