74 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has tried to light several times but failed, so it has locked itself for safety.
Your boiler has switched itself off because it has detected that the water inside has become too hot.
Your boiler has stopped working to prevent a technical fault from causing damage, essentially 'tripping' itself off like a fuse.
Your boiler has stopped working because the water pressure is either too low, too high, or the water isn't moving through the system correctly.
Your boiler has detected an issue with the ventilation fan, which means it cannot safely clear exhaust fumes and will not ignite.
Your boiler has detected a fault with the sensor that monitors the temperature of the water leaving the unit to heat your radiators.
Your boiler is struggling to accurately measure the temperature of your hot water due to a faulty internal sensor.
Your boiler's outside temperature sensor has failed, meaning the system doesn't know how hard it needs to work to heat your home based on the weather.
Your boiler has shut down because it has detected an unsafe build-up of heat or exhaust gases in the flue system.
Your boiler has shut down because it detected that the exhaust gases have become dangerously hot, potentially damaging internal safety components.
Your boiler is detecting a flame when it shouldn't be there, which is a safety mechanism that prevents the system from starting up.
Your boiler has detected a problem with the sensor that monitors the temperature of the water coming back from your radiators, preventing it from heating your home safely.
Your boiler has detected a fault with a temperature sensor that monitors the water returning to the unit, causing the system to stop working for safety.
Your boiler has detected that the water is heating up too quickly or not circulating properly, causing the system to shut down to prevent overheating.
Your boiler is overheating because the water is getting too hot too quickly, usually due to a lack of proper water flow through the system.
Your boiler has likely overheated because water is not circulating properly through the system.
Your boiler has overheated or the water is not circulating properly through the system, causing it to shut down for safety.
Your boiler is struggling to move water through the system correctly, which is causing it to shut down to prevent overheating.
Your boiler has likely stopped working because water is not moving through the system quickly enough to prevent it from overheating.
Your boiler has sensed that the exhaust gases are getting too hot and has shut down as a safety precaution.
Your boiler has shut down because the internal exhaust gases have reached a temperature that is dangerously high.
Your boiler has detected that the water isn't heating up or circulating correctly immediately after starting, causing it to shut down for safety.
Your boiler has stopped working because it cannot detect the water temperature rising quickly enough after firing up.
Your boiler has detected a problem with one of its internal monitoring sensors, which is preventing the system from operating correctly.
Your boiler's internal monitoring system has detected a fault with one of its temperature sensors, which is preventing the unit from operating correctly.
Your boiler has detected an internal electronic failure and has shut down for safety because it cannot correctly control the gas valve.
Your boiler has detected an internal electrical fault with the gas valve control system and has shut down for safety.
Your boiler has stopped working because its internal safety computer cannot correctly control the gas valve, meaning the boiler has locked itself out for safety.
Your boiler's main control board has detected a failure in the internal switch that controls the gas valve, preventing the system from firing up for safety.
Your boiler has detected a flame that continues to burn even after the gas valve should have closed, which is a safety fault that requires a professional inspection.
Your boiler is unable to control the flame size properly because a key electronic connection to the gas control system has failed.
Your boiler is unable to control its heat levels properly because a key internal communication cable has come loose or failed.
Your boiler has sensed a blockage or issue with the flue pipe that safely carries exhaust fumes out of your home, causing it to shut down for safety.
Your boiler has detected that waste gases cannot properly escape through the flue pipe, causing the system to shut down for safety.
Your boiler is failing to keep the flame lit and has locked itself out after several unsuccessful attempts to stay running.
Your boiler is repeatedly failing to keep a steady flame, causing it to shut down for safety.
Your boiler has detected that its internal temperature sensors are giving very different readings, causing the system to shut down for safety.
Your boiler has detected that its temperature sensors disagree with each other, so it has shut down as a safety precaution.
Your boiler has detected an issue with the electrical power timing reaching the unit, which is preventing it from running safely.
Your boiler is struggling to operate because the electrical power entering the unit does not match the required frequency standards.
Buttons on the control panel appear to be stuck or are not communicating correctly with the boiler's internal computer.
Your boiler’s control panel buttons are stuck or faulty, preventing you from changing settings or resetting the unit.
Your boiler has stopped working because the water pressure is too low or it is struggling to light the burner.
Your boiler is having trouble talking to its smart thermostat or external controller, meaning it may not receive instructions to turn the heating on.
Your boiler is having trouble 'talking' to your smart thermostat or external controls, meaning it cannot receive instructions to provide heating or hot water.
Your boiler needs to perform an automatic self-calibration of its gas valve and combustion settings to ensure it operates efficiently.
Your boiler is requesting a system recalibration to ensure the gas and air are burning correctly and efficiently.
Your boiler is struggling to maintain a stable flame because the internal controls are detecting that the gas is not burning correctly.
Your boiler is struggling to manage the flame correctly and has shut down as a safety precaution because it cannot maintain a stable burn.
Your boiler is struggling to get enough gas to stay lit, which has caused it to stop working as a safety precaution.
Your boiler is struggling to get enough gas to stay lit, which means it cannot heat your home or water safely.
Your boiler's internal computer has lost its settings and cannot correctly control the power of the burner.
Your boiler is struggling to get enough gas to stay lit, which has caused it to stop working for safety reasons.
Your boiler is struggling to receive enough gas to operate correctly and has shut down as a safety precaution.
Your boiler's electronic brain is struggling to properly manage the heat output, which usually means it cannot control the gas flow correctly.
Your boiler's electronic brain is having trouble communicating with the internal gas control valve, preventing the system from regulating the flame height correctly.
Your boiler's internal computer has encountered a technical glitch or an issue with the electrical power coming into your home.
Your boiler has detected an internal computer error or an unstable electrical supply, which is preventing it from running safely.
Your boiler has stopped working because it has been reset too many times in a short period and has now locked itself for safety.
Your boiler has been reset too many times in a short period and has now permanently locked itself for safety.
Your boiler has detected an issue with the electrical power supply coming into your home, meaning the electrical timing does not match what the boiler requires to run safely.
Your boiler is struggling to process the electricity supply because the power frequency coming into your home is not stable or is incorrect.
Your boiler is not receiving the correct amount of electrical power to operate safely and has shut down as a precaution.
The internal computer in your boiler has lost its settings and does not know how to operate the unit correctly.
Your boiler has switched itself off because it has detected that the internal water temperature has become too hot.
Your boiler has detected that the electrical wiring in your home or the plug is connected the wrong way round, preventing it from starting safely.
Your boiler has detected that the exhaust gases are getting too hot, causing it to shut down for safety.
Your boiler's internal thermometer that measures the temperature of the water flowing to your radiators has developed a fault and can no longer read the temperature correctly.
Your boiler has shut down because a sensor has detected that the water leaving the unit to heat your radiators is getting too hot.
Your boiler has detected a blockage in the waste pipe that carries away excess liquid, causing the system to shut down to prevent leaks.
Your boiler is struggling to confirm that the gas has ignited properly, causing it to shut down as a safety precaution.
Your boiler is unable to light the gas burner because it isn't receiving any fuel, likely due to a mechanical failure or an electrical communication issue with the gas control valve.
Your boiler is struggling to light the burner, meaning it cannot heat your water or radiators.
Your boiler is struggling to keep the water at the right temperature while you are running a hot tap, causing it to protect itself by switching off.
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BoilerFaultCodes