164 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler's main control panel has lost communication with its internal electronic brain, meaning the system cannot receive or process any instructions to work.
Your boiler is struggling to push hot water through your radiators because an external pump is not responding correctly.
Your boiler is struggling to reach its full heating power because the maximum heat output setting is incorrectly configured or restricted.
Your boiler is currently cooling itself down after providing heating by keeping the pump running temporarily.
Your boiler is taking a short, temporary break to prevent the burner from turning on and off too frequently after reaching its target temperature.
Your boiler is currently showing you the temperature of the hot water as it flows through the system rather than a fault code.
Your boiler is currently reading the live temperature from the warm start sensor, which is a normal status message rather than an actual fault code.
Your boiler is currently showing you what temperature it is aiming to reach rather than a specific error or mechanical failure.
Your boiler is displaying an information code rather than a fault, showing the temperature set for the pre-heated hot water function.
Your boiler is currently receiving a signal from your thermostat or external programmer to provide heating.
Your boiler is receiving a specific temperature instruction from an external control or smart thermostat rather than using its own internal settings.
Your boiler's internal pump which circulates water to your radiators and taps has stopped working, meaning you likely have no heating or hot water.
Your boiler is having trouble communicating with the pump that provides and stores your hot water.
Your boiler is having trouble circulating hot water because of a potential issue with the internal pump or its electrical connection.
Your boiler is struggling to automatically adjust the water pump speed needed to circulate heat around your home.
Your boiler's internal pump is running at an incorrect speed, which prevents the system from moving heat to your taps or radiators effectively.
Your boiler has detected that the water returning from your radiators is too hot, causing the system to automatically reduce its power output to protect itself.
Your boiler is staying in a cooling-down phase where the pump runs continuously to prevent the internal components from overheating.
Your boiler is checking how the pump is running to move water around the system, which may cause temporary issues with heating performance.
Your boiler is notifying you that it has reached the maximum temperature limit set for heating your hot water cylinder.
Your boiler is simply indicating that it is currently processing a request for hot water.
Your boiler is currently set to summer mode, which means it will provide hot water but has temporarily disabled the central heating.
Your boiler's internal water pressure is too low for it to operate safely, causing it to shut down temporarily.
Your boiler is simply indicating that it has received a signal from an external smart thermostat or control unit to start providing hot water.
Your boiler is having trouble communicating with an internal component or external accessory that helps manage its secondary electrical functions.
Your boiler's internal control system is struggling to communicate with an external accessory or control relay, which may affect how your heating or hot water turns on.
Your boiler's internal control board is having trouble communicating with an optional plugin component, usually related to external heating controls.
Your boiler is failing to light because the main control board is not sending the necessary signal to open the gas supply valves.
Your boiler's fan is struggling to reach the correct speed required to safely push exhaust fumes out of the flue.
Your boiler has stopped working because the fan is unable to reach the correct speed for the gas to safely ignite.
Your boiler is currently set to provide warm water only and is not attempting to heat your radiators.
Your boiler is struggling to detect when you turn on a hot tap, meaning your water might stay cold or fluctuate in temperature.
Your boiler is displaying the current temperature it is aiming to reach for your heating or hot water, rather than a system fault.
Your boiler is displaying the current temperature of the water returning from your radiators rather than indicating a specific fault.
Your boiler is having trouble detecting whether the flame is burning correctly, which is preventing it from staying on for safety.
Your boiler is having trouble communicating with the outdoor sensor that helps it adjust to the weather, meaning your heating might not be as efficient as usual.
Your boiler's fan is struggling to run at the correct low speed required for efficient operation.
Your boiler's computer is reporting an internal memory error related to how it controls its fan speed.
Your boiler is currently receiving pre-heated water from your solar heating system and does not need to use gas to heat it further.
Your boiler has shut down because it has detected an unsafe build-up of heat too many times in a row, likely due to a circulation problem.
Your boiler has failed to ignite or stay lit too many times and has now locked itself out for safety reasons.
Your boiler is taking longer than expected to start up its flame, which suggests an early warning sign of a component starting to fail.
Your boiler is struggling to light its flame properly and has timed out for safety after several failed attempts.
Your boiler is temporarily resting to prevent the burner from turning on and off too frequently, which helps protect the internal components and improve efficiency.
Your boiler is struggling to light its flame on the first try, which means it may eventually fail to provide heating and hot water.
Your boiler has failed to light the flame twice in a row, meaning it cannot provide heating or hot water until the issue is resolved.
Your boiler is currently stuck in a diagnostic test mode used to check the internal valve that directs hot water to either your taps or your radiators.
Your boiler's heating temperature dial is set to its maximum power level, which is more of a status notification than a dangerous fault.
Your boiler is briefly running its internal pump after heating your water to help cool the components down and prevent overheating.
Your boiler is experiencing a slight calibration issue with its quick-start hot water feature, meaning it might take a moment longer to heat up than usual.
Your boiler is taking too long to heat up your hot water cylinder, causing it to stop the process for safety.
Your boiler is taking a planned temporary break to prevent the burner from switching on and off too frequently, which protects the components from unnecessary wear.
Your boiler is limiting the amount of power it uses to heat your hot water, likely due to a sensor detecting that heat isn't being transferred quickly enough.
Your boiler is limiting the temperature used to heat your hot water, which usually means it is trying to prevent internal overheating or scale build-up.
This is not an error code, but simply a status message on your boiler's screen showing how many hours the heating system has been running.
This is a status code rather than a fault, showing you how long the boiler has spent heating your hot water.
Your boiler is simply indicating that it is starting the process of heating your radiators, which is a normal status message rather than an actual fault.
Your boiler is letting you know it has started up specifically to provide hot water to your taps.
Your boiler is simply reminding you that a routine service is due soon based on its operating hours.
Your boiler's internal computer is currently processing data or communicating with an external smart thermostat, which is a normal status check and not a hardware failure.
Your boiler is displaying a communication status message regarding an external weather sensor and does not indicate a breakdown.
Your boiler has lost its internal identity and no longer knows which specific model it is supposed to be, usually following a parts change.
Your boiler has reverted to its original factory settings and needs its specific configuration data re-entered to work correctly.
Your boiler has entered a specialist programming menu typically used by engineers to change background settings, which means it may not operate as normal until exited.
Your boiler has detected a specific internal system fault that requires a professional diagnosis to identify which component has failed.
Your boiler has lost connection to its flow temperature sensor, meaning it cannot accurately monitor the water temperature inside and has shut down as a safety precaution.
Your boiler has stopped working because it cannot communicate with the internal sensor that monitors the temperature of the water leaving the unit.
Your boiler has stopped working because an internal temperature sensor or its wiring has failed, meaning it can no longer safely monitor the water temperature.
Your boiler has failed to ignite, which means it cannot provide the heating or hot water you need.
Your boiler has detected a disconnected or faulty sensor that monitors the water returning to the system, causing the unit to stop working for safety.
Your boiler is attempting to start but cannot successfully light the gas flame to provide heat or hot water.
Your boiler has shut down because it grew too hot and reached its safety temperature limit.
Your boiler's internal temperature sensor has stopped sending the correct information to the control board, preventing the system from heating up.
Your boiler's internal sensor that monitors the flow of water has a loose connection or a wiring fault, causing the system to stop working for safety.
Your boiler has detected that water isn't moving through the unit properly, causing it to stop for safety.
Your boiler has detected an internal blockage that is preventing water from circulating properly, causing it to stop its heating functions to protect itself.
Your boiler has detected an electrical short circuit in its internal wiring or sensors, preventing it from starting up safely.
Your boiler has detected an issue with the electrical supply wiring being reversed or a problem with the internal earthing.
Your boiler has switched itself off because it has become too hot inside and needs time to cool down before it can restart.
Your boiler has failed to ignite or stay lit, meaning it cannot provide heating or hot water until the ignition system is fixed.
Your boiler has detected that there is not enough water pressure in the system to operate safely, causing it to shut down to prevent overheating.
Your boiler has shut down because the water is heating up too quickly and the temperature difference between the pipes is too large, usually caused by a circulation problem.
Your boiler has stopped working because water is not flowing through the system properly, which is likely caused by a lack of pressure, a pump issue, or a blockage.
Your boiler has shut down because it detected that the exhaust gases are getting too hot, indicating a potential internal blockage or a circulation problem.
Your boiler has detected a problem with the gas valve and has shut down as a safety precaution because it cannot correctly manage the flow of fuel.
Your boiler thinks it sees a flame even though it hasn't actually started the ignition process, causing it to shut down for safety.
Your boiler is failing to light the gas flame required to provide heating and hot water.
Your boiler has lost its flame while running and cannot stay lit, meaning your heating and hot water will stop working.
Your boiler has detected an issue with the fan, meaning it cannot safely clear exhaust gases and will not fire up to provide heat or hot water.
Your boiler is having trouble communicating with its internal controls or external thermostat due to an electrical wiring issue.
Your boiler has detected an internal electronic failure that is preventing the gas valve from operating safely, which means your heating and hot water will not work.
Your boiler is unable to safely control the gas supply, meaning it cannot ignite to provide heating or hot water.
Your boiler has detected a safety issue where the gas valve is not closing properly, which could mean gas is leaking into the burner when it shouldn't be.
Your boiler's computer memory has developed a technical fault, preventing it from processing the instructions needed to run properly.
Your boiler's internal computer has detected a conflict between its sensors or an electronic error, causing the system to shut down for safety.
Your boiler's internal control board has become too hot to function, causing the system to shut down for safety.
Your boiler's internal computer is receiving a confused signal from the flame sensor, preventing the system from heating up as a safety precaution.
Your boiler is struggling to keep its flame lit because air has likely mixed with the gas supply or the flame sensor is failing to detect the heat.
Your boiler’s control computer has lost its identity settings and no longer recognises which specific model it is supposed to be operating.
Your boiler has detected that a temperature sensor is stuck on a single reading and cannot accurately tell how hot the water is, so it has shut down for safety.
Your boiler has detected that the water flowing out is heating up much faster than the returning water, suggesting a sensor fault or a blockage in the system.
Your boiler has detected an issue with its internal pressure sensor, meaning it cannot accurately tell how much water is in the system.
Your boiler's internal sensor has detected an unusual pressure reading and has safely shut down to prevent damage.
Your boiler is failing to start because it cannot detect the necessary rise in water pressure when the internal pump begins to run.
Your boiler has shut down because a safety sensor has detected that the main component which heats your water has become dangerously hot.
Your boiler has detected a problem with the device that removes wastewater or the flap that seals the exhaust pipe, causing it to shut down for safety.
Your boiler has lost communication with the hot water temperature sensor, meaning it cannot accurately heat your water for taps and showers.
Your boiler is not firing up because it cannot detect a clear change in temperature after it starts the burner.
Your boiler has noticed that its internal temperature sensors are giving conflicting or illogical readings, which prevents it from heating up safely.
Your boiler has detected that the temperature sensors are giving unusual readings, likely because they have become loose or were not installed correctly onto the internal pipes.
Your boiler is currently running an automatic program to clear air bubbles out of the heating and hot water systems.
Your boiler is struggling to complete a diagnostic check because it cannot maintain its maximum power level correctly.
Your boiler is not broken; it is simply running a manual test mode to check how it performs at its lowest power setting.
Your boiler is currently running a self-diagnostic test to help fill the central heating system and remove trapped air.
Your boiler is currently on standby because it hasn't received a signal from your thermostat to turn the heating on.
Your boiler is unable to start its heating process because the internal fan, which safely clears waste gases, is failing to spin up properly.
Your boiler is currently preparing to turn on the heating and is in the process of starting up the internal fan.
Your boiler is struggling to circulate water properly around the system, which is preventing it from heating up correctly.
Your boiler is currently preparing to provide heating and is checking that water is moving correctly through the system.
Your boiler is struggling to light the burner to provide central heating, meaning your radiators will not warm up.
Your boiler is trying to start up to provide heating, but it keeps failing to light the burner successfully.
Your boiler is currently firing up and heating your radiators exactly as it should be.
Your boiler is operating normally and is currently firing the burner to provide central heating to your home.
Your boiler is failing to shut down properly after a heating cycle because the internal fan is stuck running for too long.
Your boiler is failing to clear leftover gases after a heating cycle because the internal fan is not spinning down as expected.
Your boiler has finished its heating cycle but is struggling to circulate water to cool itself down correctly, which can cause the system to pause.
Your boiler has finished its heating cycle and is now keeping the internal pump running for a short time to safely cool down the internal components.
Your boiler is temporarily pausing the heating because it has reached its target temperature and is waiting for a short period before restarting to prevent unnecessary wear.
Your boiler is temporarily resting because it reached its target temperature and is waiting for a short period before restarting to prevent excessive wear.
Your boiler has detected that you have turned on a hot water tap and is currently preparing to heat the water for you.
Your boiler is trying to provide hot water but cannot safely start the internal fan required to clear exhaust fumes.
Your boiler is not providing hot water because the internal fan is not spinning fast enough to safely start the heating process.
Your boiler is briefly keeping the internal fan and pump running to clear away excess heat after you have finished using hot water.
Your boiler has detected an issue with the fan after you finished using hot water, preventing it from clearing residual gases correctly.
Your boiler has finished providing hot water, but the pump is struggling to circulate the remaining heat away from the system, likely due to a blockage or a valve issue.
Your boiler has received a request to provide hot water, but it is taking longer than expected to start the heating process.
Your boiler is trying to provide hot water, but the internal fan that clears away waste gases is failing to start up properly.
Your boiler has detected that water isn't moving through the system properly while trying to provide hot water.
Your boiler is failing to light the burner when you turn on your hot water tap.
Your boiler is simply letting you know that it is currently busy heating up water for your taps.
Your boiler is pausing after a period of providing hot water because it has detected an issue with the internal cooling process involving the pump or fan.
Your boiler is briefly cooling itself down after you have used the hot water, which is a normal part of its operation.
Your boiler is temporarily running the internal pump after you have turned off the hot tap to help the system cool down safely.
Your boiler is temporarily pausing the burner to prevent it from switching on and off too frequently while heating your water.
Your boiler is working fine, but your wall thermostat is currently telling it to stay switched off because your home is already at the desired temperature.
Your boiler is currently set to summer mode, which means it is ignoring the thermostat and will only provide hot water, not heating.
Your boiler is temporarily pausing because the fan is not spinning at the correct speed needed to safely clear exhaust fumes.
Your boiler has entered a temporary frost protection mode to prevent internal pipes from freezing due to very low temperatures.
Your boiler is currently set to a mode where it isn't asking for heat because it doesn't think any is needed based on your external controls.
Your boiler has temporarily stopped heating because a safety sensor or an external pump has detected an issue and cut the power to the burner.
Your boiler has detected an internal issue and is running at a lower power level to keep providing some heat while protecting itself from damage.
Your boiler has stopped working because the water pressure inside the system is too high.
Your boiler has paused operation because a safety flap in the flue system is stuck or sending an incorrect signal, preventing waste gases from being cleared safely.
Your boiler is struggling to maintain a small flame when it tries to run at its lowest power setting, causing it to shut down for safety.
Your boiler has temporarily paused because it is struggling to move enough water through the system, likely due to low pressure or a blockage.
Your boiler has temporarily paused its operation because it has detected a problem with getting water through the system quickly enough.
Your boiler is temporarily pausing to prevent overheating after reaching a high temperature, often due to a lack of proper water flow.
Your boiler is temporarily limiting its power because strong wind or a blockage is interfering with how the flames burn.
Your boiler has failed an internal test to identify the specific type of gas being supplied, which has caused it to stop running for safety.
Your boiler is struggling to move enough water through the system to operate safely and effectively.
Your boiler has detected a problem with the sensor that monitors water temperature returning from your radiators, preventing it from heating your home efficiently.
Your boiler is temporarily pausing to double-check its internal sensors to ensure the temperature readings are accurate before starting up.
Your boiler is currently in standby mode because it hasn't received a signal from your thermostat to turn the heating on.
Your boiler is struggling to light the flame specifically when you turn on your hot water taps.
BoilerFaultCodes