164 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler's internal computer is having trouble talking to its main control board, meaning the system cannot start up or operate.
Your boiler is having trouble communicating with the external pump that moves hot water around your radiators, meaning your heating likely won't work.
Your boiler is currently set to run at a lower power than needed, meaning your radiators might take a long time to heat up or may not get as hot as they should.
Your boiler is currently cooling itself down after providing heating, which is a normal operating status rather than an actual fault.
Your boiler has temporarily paused its burner to prevent it from switching on and off too frequently, which helps protect the internal components and improve efficiency.
Your boiler is currently showing the temperature of the hot water as it flows through the system, which is a normal status message rather than an error.
Your boiler is providing an informational update on the current temperature of its internal warm start feature and is not reporting a fault.
Your boiler is currently waiting for the water to reach the correct temperature before it begins its next heating cycle.
Your boiler is displaying an information code rather than a fault, indicating the current target temperature for the pre-heated hot water function.
Your boiler is receiving a signal from a remote device, such as a thermostat or timer, telling it to turn on and provide heat.
Your boiler is being told what temperature to run at by an external smart thermostat or control dial, rather than its own internal settings.
Your boiler's internal pump is not circulating water correctly, which means your heating and hot water cannot function.
Your boiler is having trouble communicating with the external pump responsible for heating your hot water cylinder.
Your boiler is having trouble circulating hot water around your home due to a potential electrical or mechanical issue with the internal pump.
Your boiler is struggling to control the speed of the pump that moves hot water around your pipes and radiators.
Your boiler is struggling to accurately monitor or control the speed of the pump that circulates water through your radiators.
Your boiler is sensing that the water returning from your radiators is too hot, causing it to switch from a high-power mode to a low-power maintenance mode.
Your boiler is currently set to run the internal pump continuously rather than only when needed for heating or hot water.
Your boiler is currently switching between different pump speeds to manage the flow of water through your heating system.
Your boiler is notifying you that the hot water cylinder has reached its maximum temperature setting and is waiting to cool down.
Your boiler is letting you know that a hot water tap is currently turned on or being requested.
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 the system to operate safely.
Your boiler is currently heating your hot water because it has received a signal from your external thermostat or controller.
Your boiler's electronic control board is having trouble communicating with an internal switch that manages external components like a pump or valve.
Your boiler's internal control board is having trouble communicating with an electrical switch that operates your heating or hot water components.
Your boiler is having trouble communicating with an external control or component connected to its secondary switch relay.
Your boiler's main control board is currently unable to communicate with the gas valves that provide fuel for the flame.
Your boiler's fan is not reaching the correct speed required to safely clear exhaust fumes, meaning the system cannot start its ignition sequence.
Your boiler is struggling to monitor or control the speed of its fan, which is preventing it from safely clearing away waste gases.
Your boiler is struggling to bring the heating up to temperature, likely because there is air trapped in the system or the water pressure is too low.
Your boiler is struggling to detect when you turn on a hot tap, meaning you might have inconsistent or no hot water.
Your boiler is currently showing you what temperature it is aiming to reach rather than a specific fault code.
Your boiler is displaying the current temperature of the water returning from your radiators to help you monitor its performance.
Your boiler is having trouble detecting the flame properly, which prevents it from firing up safely to provide heating and hot water.
Your boiler is having trouble communicating with the outdoor temperature sensor that helps it adjust to the weather.
Your boiler is providing a diagnostic message about an internal fan speed setting rather than a breakdown code, often appearing during initial setup or after maintenance.
Your boiler's fan speed is slightly out of its normal operating range, meaning the system is struggling to regulate the air and gas mixture correctly.
Your boiler is currently taking advantage of heat from your solar panels to help warm up your water, which is a normal energy-saving function.
Your boiler has switched itself off several times because it reached an unsafe internal temperature, likely due to a circulation problem.
Your boiler has recorded several failed attempts to start up and is now preventing the system from running to protect itself from damage.
Your boiler is struggling to light consistently, meaning it is taking longer than usual to ignite the gas and start heating.
Your boiler is struggling to light its flame properly and is cutting out for safety after trying for too long.
Your boiler is taking a short, programmed break to prevent itself from turning on and off too frequently, which protects the internal components from unnecessary wear.
Your boiler is struggling to light the flame on its first try, which often means it is having trouble with its fuel supply or the spark.
Your boiler has tried and failed to light the flame twice in a row, meaning your heating and hot water will not work.
Your boiler is currently stuck in a diagnostic test mode used to check if the internal valve is pointing toward the radiators or the hot water.
Your boiler is currently set to provide its maximum possible heat output, which can cause it to use more energy and might lead to overheating issues.
Your boiler is briefly running the pump after heating water to prevent the internal parts from getting too hot.
Your boiler is notifying you that it has adjusted its settings to manage how it keeps water warm for quicker delivery to your taps.
Your boiler is taking too long to heat up your hot water cylinder, which usually means there is a problem with the sensor or the water flow between the boiler and the tank.
Your boiler is taking a planned short break to prevent itself from turning on and off too frequently, which helps save energy and protect the internal parts.
Your boiler is currently limiting the amount of energy it uses to heat your hot water cylinder, which may result in your water taking longer to warm up.
Your boiler is limiting the maximum temperature it uses to heat your hot water cylinder, which may mean your water takes longer to heat up or doesn't feel as hot as usual.
This is not an error code, but an information readout showing the total number of hours your boiler has spent providing central heating.
This is an information code rather than a fault, showing you the total number of hours the boiler has spent heating your water.
Your boiler is notifying you that it is currently firing up to start providing heat for your radiators.
Your boiler is notifying you that it has started a burner cycle specifically to provide hot water, though this may occasionally signal a sensor mismatch.
Your boiler is simply reminding you that a routine service is due soon based on the number of operating hours it has completed.
Your boiler is currently communicating with an external room thermostat or digital controller, and this code is simply a status update rather than a mechanical fault.
Your boiler is checking for an external radio signal to automatically set the time and date using its outside sensor.
Your boiler has lost its identity settings, meaning it has forgotten exactly which model it is and cannot operate safely until it is reprogrammed.
Your boiler is currently resetting its internal software to the original factory settings, often after a control board replacement.
Your boiler has entered a specialist programming mode used by engineers to perform advanced system checks or adjustments.
Your boiler has detected an internal electronic error that it cannot resolve on its own, stopping it from operating safely.
Your boiler has lost connection with its internal temperature sensor, preventing it from heating your water safely.
Your boiler has lost its connection to the sensor that monitors the temperature of the water leaving the unit, meaning it cannot heat your home safely.
Your boiler has stopped working because a sensor that monitors the temperature of the water leaving the unit has developed an electrical fault.
Your boiler has failed to light because it isn't receiving enough gas or cannot create a spark to ignite the burner.
Your boiler has lost connection with the sensor that monitors water temperature coming back from your radiators, causing it to stop working for safety.
Your boiler is failing to light the flame needed to heat your water or radiators.
Your boiler has sensed it is getting too hot and has shut down as a safety precaution to prevent damage.
Your boiler's internal temperature sensor has stopped sending information correctly, meaning the system doesn't know how hot the water is and has shut down as a precaution.
Your boiler's internal sensor has detected a broken connection, which means it cannot accurately measure the temperature needed to function properly.
Your boiler has detected a internal blockage that is stopping the water from circulating around your heating system correctly.
Your boiler has detected an internal blockage that is preventing water from circulating properly, which could lead to overheating.
Your boiler has detected an electrical short circuit with the hot water temperature sensor, meaning it cannot correctly monitor the water temperature.
Your boiler has detected an electrical issue where the incoming power wires may be connected in the wrong order or there is an unstable voltage supply.
Your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.
Your boiler has failed to ignite the gas needed to create heat, meaning the system has shut down for safety.
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 there is a significant temperature difference between the water going out and the water coming back, usually caused by a blockage or a pump failure.
Your boiler is struggling to move water through the system, which is causing it to stop running to prevent overheating.
Your boiler has shut down because the exhaust gases are getting too hot, which is a safety precaution to prevent damage.
Your boiler has stopped working because it cannot properly control the flow of gas needed to stay alight.
Your boiler has detected a flame when there shouldn't be one, which has caused it to shut down for safety purposes.
Your boiler is failing to light because it isn't getting enough gas or the spark that starts the flame is not working correctly.
Your boiler has lost its flame while running and cannot stay lit, meaning your heating and hot water have stopped.
Your boiler has stopped working because the fan that removes flue gases and brings in fresh air is not spinning at the correct speed.
Your boiler has lost communication with its smart controls or accessories, likely due to a wiring issue.
Your boiler has detected an internal electrical fault with the control system that manages the gas supply, causing it to shut down for safety.
Your boiler is unable to safely control the flow of gas required to light the flame, causing the system to shut down for safety.
Your boiler has detected that the gas valve is not closing properly or is leaking internally, which is a safety concern that prevents the unit from firing up.
Your boiler's internal computer brain has developed a memory fault and can no longer process instructions safely.
Your boiler's main control computer or internal sensors have detected an electrical communication error and have stopped the system to prevent damage.
Your boiler's internal control board has become too hot to operate safely and has shut down to protect itself.
Your boiler's internal computer is receiving a confused signal from the flame sensor, preventing it from safely starting the burner.
Your boiler is struggling to keep a steady flame lit because the gas supply is inconsistent or contains air bubbles.
Your boiler’s control board and display screen are no longer communicating correctly because the internal identity settings have been lost or mismatched.
Your boiler's internal thermometer is stuck on a single reading, meaning the system cannot tell how hot the water is and has shut down as a safety precaution.
Your boiler has sensed a conflicting temperature reading between its internal pipes, causing it to shut down for safety.
Your boiler's internal sensor can't accurately tell how much water is in the system, so the unit has shut down to avoid damage.
Your boiler has detected an electrical issue with its internal pressure sensor, meaning it cannot accurately tell how much water is in the system.
Your boiler has stopped working because it cannot detect the expected rise in water pressure when the internal pump starts up.
Your boiler has shut down because a safety sensor has detected that the internal heat exchanger is getting too hot.
Your boiler has detected a problem with the pump that removes wastewater or an issue with the flap that prevents gases from flowing back into the system.
Your boiler is having trouble communicating with the hot water temperature sensor because of a broken wire or a loose connection.
Your boiler has detected that no temperature change is occurring when the burner is lit, which usually means the water is not circulating correctly or the sensors are misreading.
Your boiler has noticed that its internal temperature sensors are giving conflicting or illogical readings, suggesting they are broken or incorrectly installed.
Your boiler has detected that its temperature sensors are not reading correctly, likely because they have come loose or were installed on the wrong pipes.
Your boiler is currently running a self-cleaning routine to remove trapped air from the pipes and is not actually reporting a hardware fault.
Your boiler is currently stuck in a special high-performance testing mode and has failed to complete its internal check.
Your boiler is currently running a special test mode at its lowest power setting to check for performance or stability.
Your boiler is currently running a self-diagnostic test to help fill the system with water and remove air pockets.
Your boiler is currently in standby mode because your thermostat or programmer is not telling it to turn the heating on.
Your boiler is unable to start its fan, which is preventing the system from safely beginning the ignition process for heating or hot water.
Your boiler is currently beginning the process of starting up the fan to clear the system before the heating ignites.
Your boiler is struggling to circulate water because it has detected a problem with the flow from the pump.
Your boiler is currently preparing to provide heat and is circulating water through the system before the burner ignites.
Your boiler is struggling to light the burner to provide heating, which means your radiators will stay cold.
Your boiler is struggling to light the flame needed for heating.
Your boiler is currently firing up to provide central heating and is functioning as normal.
Your boiler is currently working as it should and the burner has successfully lit to provide central heating.
Your boiler's fan is running for longer than expected after a heating cycle, preventing the system from restarting properly.
Your boiler is struggling to clear leftover gases from the internal system after the heating cycle has finished.
Your boiler is staying in a cooling-down phase for longer than expected after the heating has finished.
Your boiler is staying in a cooling-down phase for too long after being used because it thinks water is still moving through the pipes when it shouldn't be.
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 currently taking a temporary planned break to prevent it from turning on and off too frequently, which helps protect the internal components.
Your boiler has detected that a hot water tap is turned on and is preparing to heat water for you.
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 is failing to start even though you have turned on a hot tap because it cannot detect the air flow needed to run safely.
Your boiler is temporarily cooling itself down after you have used the hot water taps.
Your boiler has detected an issue with the fan after it has finished heating your hot water, preventing it from starting the next cycle properly.
Your boiler is struggling to circulate water properly after providing hot water, which is causing it to pause for safety.
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 is failing to start up properly to clear the exhaust gases.
Your boiler is having trouble circulating hot water because the pump isn't detecting enough water flow or has become stuck.
Your boiler is struggling to light properly when you turn on your hot water taps.
Your boiler is currently working as it should by firing the burner to provide hot water to your taps or shower.
Your boiler is currently cooling itself down after providing hot water and will be temporarily unavailable for a few minutes.
Your boiler is staying in a cooling-down phase for the hot water system because it thinks the fan or air pressure sensor has not switched off yet.
Your boiler is temporarily running its internal pump to cool down the internal components after you have finished using hot water.
Your boiler is temporarily pausing the burner to prevent it from switching on and off too frequently while heating your water.
Your thermostat has told the boiler not to turn on the heating, likely because it is set too low or has lost connection.
Your boiler is currently set to summer mode, which means it will provide hot water but is intentionally ignoring requests to turn on your central heating.
Your boiler is temporarily paused because the internal fan isn't spinning at the correct speed to safely clear exhaust fumes.
Your boiler has detected that the temperature is too low and has paused itself to prevent the pipework from freezing.
Your boiler is in a standby mode because it hasn't received a signal from your thermostat to start heating.
Your boiler has paused its operation because a safety sensor has detected that an external component, such as an overflow pump or a temperature limit switch, has been triggered.
Your boiler has detected a minor inconsistency in its temperature readings and has entered a restricted performance mode to keep providing some heat while protecting the internal components.
Your boiler has detected that the water pressure is too high, often caused by the filling loop being left open or a fault in the expansion system.
Your boiler has paused operation because a safety flap in the flue system is not opening or closing correctly, preventing waste gases from being safely cleared.
Your boiler is struggling to maintain a steady flame when running at its lowest power setting, which may cause it to stop working unexpectedly.
Your boiler has temporarily paused because it cannot sense enough water flowing through the system to operate safely.
Your boiler has temporarily paused its heating process because it has detected a sudden rise in temperature and needs time to cool down before restarting.
Your boiler is temporarily pausing operation because it has detected a potential issue with the burner flame not settling properly during its warm-up phase.
Your boiler is temporarily limiting its power because strong wind or a blockage is interfering with how the burner operates.
Your boiler has failed an internal test to confirm it is burning the correct type of gas, causing it to shut down for safety.
Your boiler is struggling to move enough water through the system, usually due to a blockage, air bubbles, or a problem with the pump.
Your boiler has detected an issue with the sensor that monitors the temperature of the water coming back from your radiators, preventing it from heating correctly.
Your boiler is temporarily paused because it has detected a mismatch between the temperature sensors and needs to double-check them before starting up.
Your boiler is 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