53 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has failed to complete its necessary initial setup and self-calibration process, preventing it from running safely.
The main computer boards inside your boiler are having trouble talking to each other, causing the system to shut down.
Your boiler has tried to light several times and failed, so it has locked itself out to prevent further wasted attempts.
Your boiler detects a flame when there shouldn't be one, which is a safety conflict that prevents the system from starting.
Your boiler has failed to stay lit too many times and has locked itself out for safety.
Your boiler's internal computer parts are having trouble communicating with each other, meaning the system cannot send or receive the signals needed to stay running.
Your boiler is not detecting a flame when it tries to start, meaning your heating and hot water will not work.
Your boiler has detected an internal electrical conflict between the power supply and the flame detection system, preventing it from firing up safely.
Your boiler has sensed that it is getting dangerously hot and has shut itself down to prevent damage to the internal components.
Your boiler has detected an internal electronic or mechanical failure with the component that controls the gas supply, meaning it cannot ignite safely for heating or hot water.
Your boiler has stopped working because the fan that helps remove waste gases is not spinning correctly or communicating with the system.
Your boiler has stopped working because the fan that removes waste gases cannot spin, likely due to a physical obstruction or a mechanical fault.
The fan that pushes harmful gases out of your boiler has stopped spinning or is stuck, preventing the boiler from starting for safety reasons.
Your boiler's fan has failed or is spinning at the wrong speed, preventing the unit from clearing exhaust fumes and starting safely.
Your boiler has detected a blockage or a problem with the air flow in the flue pipe before it even starts the ignition process.
Your boiler has detected that waste gases are not leaving the system correctly, causing it to shut down for safety.
Your boiler has detected a blockage in the flue pipe that prevents exhaust gases from escaping safely, causing the system to shut down for your protection.
Your boiler has failed a safety check because the flame was not burning correctly at low power, causing the system to shut down for protection.
Your boiler has detected that the gas is not burning correctly when running at full strength, so it has shut down for safety.
Your boiler has detected an unusual flame or electrical signal that suggests the burner is not firing correctly or safely.
Your boiler has detected that there is not enough water in the system to operate safely and has shut down as a result.
Your boiler has detected that the water pressure is dropping too low, which is stopping it from working correctly.
Your boiler has stopped working because it cannot accurately detect if there is enough water inside the system to operate safely.
Your boiler has detected a blockage or a fault in the flue pipe that is preventing exhaust fumes from escaping safely.
Your boiler has detected a blockage or restriction in the flue pipe that is preventing exhaust fumes from escaping safely at high power.
Your boiler's main internal computer has detected an electrical fault and has shut down as a safety precaution.
Your boiler's main control board is unable to talk to the fan, which is preventing the system from starting up safely.
The boiler's control system has lost communication with its internal computer, meaning it can no longer process instructions to heat your home.
Your boiler’s internal computer chip has lost its settings or is having trouble communicating with the control board.
Your boiler's internal computer has detected a communication failure with the ignition control system, preventing it from firing up.
Your boiler's central heating sensor has detected a fault, meaning the system cannot accurately monitor the temperature of the water used to heat your radiators.
Your boiler has sensed that the water inside the central heating system has become dangerously hot and has shut down as a safety precaution.
Your boiler has detected that the water coming back from your radiators is at an unusual temperature compared to the water going out, often meaning something is blocking the flow.
Your boiler is struggling to control the flow of water because an internal valve is not reaching the position it needs to be in.
Your boiler has lost connection with the device that tells it how to heat your low-temperature heating circuit, meaning it cannot communicate correctly to start the heating.
Your boiler has stopped working because it cannot correctly measure the temperature of the water returning from your radiators.
Your boiler has shut down because the water returning from your radiators is too hot, suggesting a block or a circulation problem.
The water is heating up too quickly or there is a large temperature difference within the boiler, suggesting that water is not flowing through the system as fast as it should.
Your boiler has detected an internal electronics communication error, which means it cannot safely process the commands to heat your home.
Your boiler has detected an issue with the sensor that monitors exhaust gases, and it has shut down for safety to prevent overheating or poor combustion.
Your boiler has failed to complete its automatic self-tuning process and has shut down as a safety precaution.
Your boiler has unsuccessfully tried to adjust its internal settings too many times and has locked itself out for safety.
The boiler's internal sensor has detected that the gas and air mixture is incorrect, preventing the burner from operating safely.
Your boiler has failed its internal self-tuning process and has shut down as a safety precaution.
Your boiler has shut down because the internal combustion sensor has detected that the gas and air mixture is outside of safe operating limits.
Your boiler has failed an internal safety check during startup and has locked itself out to prevent a malfunction.
Your boiler has suffered an internal electronic communication failure that has prevented it from starting up correctly.
Your boiler has been manually reset too many times in a short period and has now locked itself out for safety.
Your boiler has detected that the water pressure in the central heating system is too low to operate safely.
Your boiler's internal computer chips are failing to communicate because their software versions do not match, preventing the system from operating.
Your boiler's internal computer has encountered a software error that has caused it to stop working for safety.
Your boiler's internal timer or control clock has stopped working correctly, which may prevent your heating from turning on according to your schedule.
Your boiler is working fine but has reached its set service interval and needs a routine checkup by a professional.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes