94 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has lost its connection to the temperature sensor, meaning it no longer knows how hot the water is and has stopped working to keep you safe.
Your boiler has lost the connection to the sensor that monitors the temperature of the water returning to the unit, causing it to stop working for safety reasons.
Your boiler has detected a communication issue with the built-in hot water storage cylinder temperature sensor.
Your boiler has lost communication with the built-in hot water storage tank sensor, which means it may struggle to provide consistent hot water.
Your boiler has stopped working because one of its internal sensors has developed an electrical fault and can no longer measure the temperature of the water leaving the unit.
Your boiler has detected an electrical fault with the sensor that monitors water returning from your radiators, causing the system to shut down for safety.
Your boiler has detected an electrical wiring or sensor fault related to how it heats your hot water cylinder.
Your boiler has detected a faulty electrical signal from the temperature sensor that monitors your hot water cylinder.
Your boiler has detected that it is getting too hot and has automatically shut down to prevent damage or overheating.
Your boiler has temporarily stopped working because the water pressure inside the system has dropped too low.
Your boiler has detected that the water inside it is heating up or moving much faster than expected, so it has shut itself down to prevent any damage.
Your boiler has detected that the water inside it is heating up much faster than it safely should, causing it to shut down to prevent damage.
Your boiler has detected that the gases it is producing are too hot to be safe, so it has automatically shut down to prevent damage.
Your boiler is unable to open the internal valve that supplies gas to the burner, meaning it cannot ignite to provide heat or hot water.
Your boiler has detected a signal that suggests a flame is present even when the burner is turned off, causing it to shut down for your safety.
Your boiler is trying to start but cannot get the flame to light or stay lit.
Your boiler was working but has suddenly turned off because the flame has gone out and it cannot manage to relight itself.
Your boiler has detected that the internal fan responsible for safely venting exhaust gases is not spinning, so it has shut down to prevent unsafe operation.
Your boiler is having trouble identifying its own internal settings due to a connection error between its electronic parts.
Your boiler is having trouble communicating with its external controllers or thermostats, preventing it from receiving instructions to heat your home.
Your boiler is having trouble measuring the air flowing into it, so it has shut down to ensure it operates safely.
Your boiler is struggling to mix the correct amount of gas and air to burn properly, so it has safely shut itself down to prevent issues.
Your boiler is failing to ignite because it is not receiving enough gas to function properly.
Your boiler has detected an issue with the system that controls the gas and air mixture required to burn fuel safely, so it has shut down to prevent any risk.
Your boiler has temporarily stopped operating to protect itself from a potential hardware fault during its startup sequence.
Your boiler has detected an internal electrical problem with the valve that controls the supply of gas inside the unit.
Your boiler has temporarily locked out because the internal gas valve took slightly too long to close safely after use.
Your boiler's internal computer has encountered a memory error and cannot read the essential configuration data required to operate safely.
Your boiler's internal computer has detected an electrical error, likely caused by a faulty sensor or a loose connection that is preventing it from operating safely.
Your boiler has detected that the temperature of its internal electronic components is too high, so it has safely shut down to prevent permanent damage.
Your boiler has detected an internal communication problem with its electronic control system, meaning it cannot safely confirm the flame is burning correctly.
Your boiler is temporarily locking out because the flame inside is flickering or going out unexpectedly, meaning you currently have no heating or hot water.
Your boiler's internal computer has forgotten its identity settings, preventing it from starting up correctly.
Your boiler is not showing proper heating temperatures because a water temperature sensor has failed or given an incorrect reading.
Your boiler is temporarily locked out because the sensors measuring water temperature are sending mismatched or incorrect readings.
Your boiler's sensor is having trouble reading the internal water pressure, which means it has safely shut down to prevent damage until the issue is resolved.
Your boiler has detected that the water pressure inside the system is currently too high.
Your boiler is locking out because it cannot detect the water pressure rising when the internal pump starts up.
Your boiler has detected an issue with the way waste water or exhaust gases are being safely cleared away.
Your boiler has lost communication with the hot water temperature sensor on your external controls or hot water cylinder.
Your boiler is having trouble communicating with an internal sensor that helps regulate hot water temperature, which means your heating or hot water may stop working.
Your boiler's built-in hot water storage tank is failing to pump water correctly, which means you will likely have no hot water available.
Your boiler is struggling to detect a normal change in water temperature, meaning it cannot accurately tell how hot the system is getting.
Your boiler has detected that the temperature sensors measuring water flow are giving conflicting readings, so it has stopped working as a safety precaution.
Your boiler has detected that the internal temperature sensors are reading values that suggest they have been fitted to the wrong pipes.
Your boiler has lost the digital connection to its internal hot water storage tank, meaning it cannot properly coordinate heating the water for your taps.
Your boiler is having trouble communicating with the internal water storage tank, which means your hot water supply may be affected or inconsistent.
Your boiler has detected an internal communication or configuration error with its main control board and cannot safely start up.
Your boiler has detected that the fuel-to-air mixture is incorrect, which means it cannot burn gas safely or efficiently.
Your boiler is currently in standby mode because it has not received a request for heating or hot water from your thermostat or taps.
Your boiler is currently just in the process of starting up its internal air fan before it begins heating your home.
Your boiler is simply preparing to heat your home by circulating water before firing up the flame.
Your boiler is currently trying to light the flame to start heating your home or water.
Your boiler is operating normally and is currently heating your radiators.
Your boiler is currently cooling itself down by circulating water and venting air, which is a normal part of the shutdown process after your heating has been running.
Your boiler is simply performing a routine safety cycle to clear any leftover heat after the burners have turned off.
Your boiler is simply finishing its cooling process after the heating has turned off, and this is a normal part of its operation.
Your boiler is simply taking a short, normal resting break between heating cycles to protect its internal parts from unnecessary wear.
Your boiler has simply detected a request for hot water and is starting its normal process to heat things up.
Your boiler is currently preparing to fire up by starting its internal fan, which is a normal part of the ignition process.
Your boiler is struggling to light its flame, which means you may experience intermittent issues with your heating and hot water.
Your boiler is currently operating normally and is heating water for your taps or shower.
Your boiler is simply finishing a cooling cycle after you have used the hot water taps, which is a normal part of its operation.
Your boiler has detected an issue with the air fan system and has temporarily stopped heating to prevent further damage.
Your boiler is currently just running its internal pump to move residual heat away from the heat exchanger after a hot water cycle, which is a normal part of its operation.
Your boiler has registered a hot water request and is operating normally to heat water for your taps.
Your boiler is currently going through its normal starting sequence to begin heating your water.
Your boiler is preparing to heat your tap water by moving the pump into position; this is a normal operational state and not an actual fault.
Your boiler is currently struggling to light the flame it needs to provide heating and hot water.
Your boiler is currently operating normally and is in the process of heating your radiators.
Your boiler is currently just finishing a routine cooling-down process after providing hot water and should return to normal operation shortly.
Your boiler's fan is attempting to spin, but the electronic control board isn't receiving the correct signal back to confirm it is working properly.
Your boiler is simply finishing its cooling cycle after providing hot water and is operating exactly as it should.
Your boiler is taking a short, programmed break to prevent the burner from starting and stopping too frequently while heating your water.
Your boiler is temporarily paused because your wall thermostat or heating controller is telling it not to send heat to your radiators.
Your boiler is simply in summer mode or not receiving a demand for heating from your thermostat.
Your boiler is temporarily pausing because the internal fan is not spinning at the correct speed needed to safely light the burner.
Your boiler has temporarily fired up its internal frost protection system to prevent the pipes from freezing during cold weather.
Your boiler has temporarily stopped heating because a safety switch—such as the one for the condensate drain—has triggered to prevent a blockage or overflow.
Your boiler has detected a minor performance issue and is operating in a temporary energy-saving mode to ensure it keeps running safely while limiting output.
Your boiler has too much water in the system, causing the pressure to rise to a level that is higher than recommended for safe operation.
Your boiler has temporarily stopped heating because a safety sensor has detected a blockage in the exhaust pathway or a problem with the water removal system.
Your boiler has temporarily lowered its heating output to prevent the flame from going out completely, usually due to a minor combustion issue.
Your boiler is pausing its operation temporarily because water is not flowing through the system properly due to low water pressure.
Your boiler has temporarily paused heating because it has detected low water pressure in the system.
Your boiler is temporarily pausing its operation to allow internal parts to cool down or stabilize, which is a normal safety feature to prevent overheating.
Your boiler has temporarily reduced its power because it is detecting unusual air movement or wind pressure in the flue system, likely due to external weather conditions.
Your boiler's computer has detected a configuration mismatch and cannot confirm it is safely set up for your home's gas supply.
Your boiler has detected that the fuel and air mixture used to heat your home is not balanced correctly, meaning it cannot operate safely or efficiently.
Your boiler has detected that the fuel-to-air mix is incorrect, which means it cannot burn gas safely or efficiently.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler is performing a routine diagnostic test on its internal temperature sensors, which temporarily pauses the heating.
Your boiler is currently running a brief self-test on its water pressure system and temporarily pausing heating until the check is complete.
Your boiler is temporarily running a self-test to check the temperature sensors, so your heating is paused for a brief moment.
BoilerFaultCodes