151 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has stopped running because it has detected a technical fault with a internal control component or the fan system.
Your boiler's internal settings may have been left in a testing mode used by engineers, preventing it from heating your home normally.
Your boiler has been left in a manual testing mode, which prevents it from operating normally to heat your home.
Your boiler’s internal computer components are not communicating correctly because they appear to be mismatched or incompatible with each other.
Your boiler's internal computer module is either incorrectly installed or is the wrong version for this specific model, causing the system to shut down.
Your boiler's computer memory chip is not communicating correctly with the main control board, preventing the system from starting up.
Your boiler is operating normally and is currently working to heat your radiators.
Your boiler is operating normally and is currently working to heat your radiators.
Your boiler is currently focused on heating your hot water taps rather than your radiators, which is a normal operating status rather than a fault.
Your boiler is simply letting you know that it is currently busy heating up your hot water.
Your boiler is working normally; it has received a signal to turn on and is currently going through its startup sequence to provide heat.
Your boiler has reached its required temperature and is taking a short, normal break to prevent itself from switching on and off too frequently.
Your boiler is currently pulse-checking and waiting for a signal to start, meaning it is powered on but not being asked to provide heating or hot water right now.
Your boiler is working correctly and is simply waiting for your thermostat or programmer to tell it to turn on.
Your boiler is temporarily pausing because the water inside it has already reached the required heat and needs a moment to cool down before firing up again.
Your boiler has stopped because the water inside it has become hotter than the temperature you have set.
Your boiler is currently running at maximum power for a flue test and will return to normal operation automatically after a short period.
Your boiler is currently stuck in a manual test mode used by engineers to check emissions, meaning it won't respond to your normal heating settings.
Your boiler is overheating because the water inside is heating up faster than it can be circulated away.
Your boiler has overheated because the water pressure is too low, and it has shut down as a safety precaution.
Your boiler has recorded that a technician's diagnostic tool was recently plugged into the control system's error history memory.
Your boiler is failing to light the fuel, meaning it cannot create the flame needed to provide you with heating and hot water.
Your boiler thinks a flame is burning even though it hasn't ignited yet, which points to an electrical or internal component error.
Your boiler's internal computer chips are using different software versions that cannot communicate with each other, preventing the boiler from starting.
Your boiler has started up, but it cannot detect the water getting any warmer, so it has shut down to prevent overheating.
Your boiler is temporarily reducing its power because it has reached the required temperature and is waiting for the heating system to catch up.
Your boiler is currently running a self-diagnostic check to ensure all parts are working correctly, which typically happens during startup or a reset.
Your boiler is working normally and is simply increasing its power to meet the heating demand.
Your boiler is currently going through its normal startup sequence and is getting ready to light the burner.
Your boiler has stopped running because it detected an internal electrical mismatch involving the gas control valve.
Your boiler is temporarily paused because it is waiting for your hot water demand to finish before it switches back to providing central heating.
Your boiler is temporarily pausing its hot water production to prevent itself from overheating or switching on and off too frequently.
Your boiler is still detecting a flame even after it has tried to shut off the fuel, which usually means a valve is stuck open or a sensor is malfunctioning.
Your boiler has detected an issue with the electrical power supply coming into your home, which is preventing it from starting up safely.
Your boiler is not receiving enough electrical power from the mains supply to operate safely and has shut down as a precaution.
Your boiler's internal computer chip does not match the main control board, preventing the system from operating correctly.
Your boiler’s internal computer chip is either missing, loose, or does not match the control board, preventing the system from starting up.
Your boiler's temperature sensor is sending incorrect information or is incorrectly positioned, preventing the system from managing heat flow properly.
Your boiler has lost its internal connection to its controls or smart thermostat system, meaning it cannot receive the signals it needs to run.
Your boiler has detected that there is not enough water in the system to operate safely and has stopped working.
Your boiler is unable to measure the temperature of your hot water, which means it cannot heat it safely or effectively.
Your boiler is struggling to monitor the temperature of your hot water, which usually means it cannot heat your water correctly.
Your boiler's outdoor thermometer is not communicating correctly, which means the system cannot adjust its heating power based on the weather outside.
Your boiler's internal computer can't tell how much water pressure is in the system because a vital sensor has either come loose or stopped working.
Your boiler has lost its connection to the outdoor thermometer, meaning it may not know how hard it needs to work to heat your home efficiently.
Your boiler has stopped working because a sensor that monitors water temperature has developed an electrical fault and can no longer report how hot the system is.
Your boiler has lost communication with the internal thermometer that monitors water temperature, causing the system to shut down for safety.
Your boiler has detected an electrical fault with its internal temperature sensor, preventing it from heating up safely.
Your boiler's main internal thermometer is failing to communicate with the brain of the system, meaning the boiler has shut down to avoid overheating.
Your boiler is struggling to detect if the burner has successfully lit, which is preventing the system from running safely.
Your boiler's control system has lost communication with the gas supply valve, meaning the unit cannot safely ignite to provide heating or hot water.
Your boiler has stopped working because its internal computer cannot communicate properly with the valve that controls the fuel flow.
Your boiler's flame has gone out while it was running, meaning the system has shut down because it can no longer generate heat.
Your boiler's internal computer memory chip is incorrect or faulty, meaning the system doesn't recognise which model it is supposed to be.
Your boiler is struggling to detect a flame and is failing to stay alight properly, which usually indicates an issue with the fuel supply or the burner settings.
Your boiler is failing to light the fuel properly, which is preventing your heating and hot water from working.
Your boiler has detected that a temperature sensor is not communicating properly, meaning the system cannot safely monitor how hot the water is getting.
Your boiler is struggling to move water through its main heating unit properly, which stops it from working to prevent overheating.
Your boiler has stopped running because the water inside it has become too hot, which is a safety measure to prevent overheating.
Your boiler is heating up too quickly, which usually means the water isn't moving through the system fast enough to take the heat away.
Your boiler has sensed a sudden, large difference in temperature between two sensors, which usually means water isn't moving through the system quickly enough to take the heat away.
Your boiler has detected that the water pressure in your heating pipes is falling much faster than expected, which usually points to a significant leak.
Your boiler has detected that the water pressure in the heating system is too low to operate safely.
Your boiler has detected that there is not enough water circulating through the system, which could be due to a leak or a pump that has seized up.
Your boiler is unable to move water around the system, usually because the pump is jammed or there is too much air trapped inside it.
Your boiler has detected an electrical fault with the sensor that monitors the temperature of the exhaust gases, causing it to shut down for safety.
Your boiler's temperature sensor for hot water has stopped working correctly, meaning your system cannot reliably tell how hot the water is.
Your boiler has lost its connection with your external thermostat or heating controls, meaning it isn't receiving the signal to turn on or off.
Your boiler is receiving an unstable or weak electrical supply, which is preventing its control computer from working correctly.
Your boiler's internal computer is having trouble reading a small memory chip that tells it exactly which model it is.
Your boiler’s internal computer has encountered a critical error and cannot communicate properly, causing the system to stop working for safety.
Your boiler has shut down because the internal fan has stopped or it cannot reliably detect the necessary air flow to stay running safely.
Your boiler's main internal computer has developed a fault and can no longer control the heating process safely.
Your boiler's safety system is detecting air movement when the fan should be off, which is usually caused by strong winds or a blocked exhaust pipe.
Your boiler has stopped working because its internal fan isn't spinning fast enough to safely clear away exhaust fumes.
Your boiler's fan is spinning faster than it should, which has caused the system to shut down for safety purposes.
Your boiler has stopped working because the internal fan isn't spinning fast enough to safely clear away exhaust fumes.
Your boiler has stopped working because the fan that clears away exhaust fumes isn't spinning or starting up properly.
Your boiler has stopped working because the internal fan isn't spinning fast enough to safely clear away exhaust fumes.
Your boiler has shut down because a vital internal fan that clears exhaust gases has stopped spinning while the heating was running.
Your boiler has lost communication with the sensor that measures the temperature outside, which helps it run more efficiently.
Your boiler has stopped working because there is not enough water in the system, usually caused by a small leak or air being bled from your radiators.
Your boiler has stopped working because the internal pump that moves water through the system is not starting or circulating correctly.
Your boiler has detected an issue with the sensor that measures the temperature of the water coming back into the system, which is usually caused by a faulty or damp component.
Your boiler has stopped working because it has lost its connection to the sensor that monitors the temperature of the water returning to the unit.
An external safety device or thermostat has stopped the boiler from running to prevent potential damage or overheating.
Your boiler is heating up much faster than it should, causing it to shut down to prevent overheating.
Your boiler has sensed that the water inside is heating up too quickly or isn't circulating properly, causing it to shut down to prevent overheating.
Your boiler has detected that the water returning to the unit is dangerously hot, causing the system to shut down for safety.
Your boiler is heating up too quickly, which usually means the water isn't moving through the system properly.
Your boiler's temperature sensor for the heating system has stopped communicating correctly, meaning the system cannot safely monitor how hot the water is.
Your boiler has detected an electrical fault with the internal sensor that monitors water temperature, causing the system to shut down for safety.
Your boiler has lost connection with the sensor that monitors water temperature, causing the system to shut down for safety.
Your boiler has lost its connection to the sensor that monitors the temperature of the water leaving the unit, meaning it cannot operate safely.
Your boiler has detected an electrical fault with the internal sensor that monitors water temperature, causing the system to shut down for safety.
Your boiler has stopped working because it cannot communicate with the part that monitors the temperature of the water flowing to your radiators.
Your boiler has stopped running because the water inside has become much too hot, suggesting it isn't moving through the system correctly.
Your boiler has overheated because the internal temperature reached a safety limit, causing the system to shut down to prevent damage.
Your boiler has shut down because a safety sensor has detected that the exhaust gases are becoming too hot.
Your boiler has switched itself off because it has detected an dangerously high temperature or a fault with its internal safety monitoring system.
Your boiler has switched itself off because it has detected an unsafe level of overheating or a critical electrical fault with its safety sensors.
Your boiler has switched itself off because it has detected that the exhaust gases have become dangerously hot.
Your boiler has become too hot and has shut itself down to prevent damage or overheating.
Your boiler has shut down because it has detected internal temperatures that are too high, causing it to overheat for safety.
Your boiler has shut down because the water coming back into the unit is far too hot, suggesting it is overheating.
Your boiler has shut down because it can no longer detect the temperature of the exhaust gases, usually due to a loose wire or a faulty internal sensor.
Your boiler has stopped working because it cannot light the fuel it needs to provide heating and hot water.
Your boiler has tried to light but cannot find a steady flame, meaning it has shut down to prevent unburnt oil from building up.
Your boiler was working but the flame has unexpectedly gone out, causing the system to stop as a safety precaution.
Your boiler has lost its connection to the fuel control system, meaning it cannot light the flame to provide heating or hot water.
Your boiler's internal computer has encountered a memory or communication error and cannot operate until it is refreshed.
Your boiler is trying to start up but is failing to light the fuel within the safe time limit, causing the system to shut down for safety.
Your boiler's computer system has detected an internal electronic fault and has stopped the burner from firing for safety.
Your boiler has slowed down because it is struggling to circulate water quickly enough through your radiators.
Your boiler's main internal computer has developed a serious communication fault or hardware failure, preventing the system from starting up.
Your boiler's internal computer is experiencing a communication failure with its electrical components, preventing it from starting up correctly.
Your boiler has experienced an internal computer glitch where the main control board has lost communication or failed its internal checks.
Your boiler has detected an internal electrical fault with the components that control the fuel supply, meaning it cannot ignite safely.
Your boiler's computer brain has malfunctioned or lost connection, meaning it cannot process commands to provide heating and hot water.
Your boiler's main internal computer has developed a communication fault and can no longer control the heating process safely.
Your boiler's internal computer or control hub has developed a fault and is unable to manage the heating process.
Your boiler's internal computer or control hub has developed a fault and is unable to communicate properly with the rest of the system.
Your boiler's internal computer has developed a fault or is not communicating properly with the main system, preventing the heater from starting.
Your boiler's internal computer has detected a communication problem with its safety sensors and has shut down to prevent damage.
Your boiler's main internal computer has developed a serious communication fault and can no longer safely operate the heating system.
Your boiler's internal computer brain or its connection chip has developed a fault or shifted out of place, causing the system to shut down.
Your boiler's electronic brains have developed a communication error or internal fault, preventing it from starting safely.
Your boiler's internal computer has lost communication with its control module, meaning the system cannot start or operate safely.
Your boiler's internal computer or control unit has encountered a serious communication error and can no longer safely operate the system.
Your boiler's main internal computer has developed a communication fault or an electronic failure, meaning it cannot control the heating process.
Your boiler thinks it can see a flame when it shouldn't be running, which is likely caused by moisture or a sensor error.
Your boiler thinks a flame is present when it shouldn't be, which is preventing the heating system from starting up safely.
Your boiler has experienced a temporary interruption in its electrical supply, similar to a brief power cut, and has paused operation as a safety precaution.
Your boiler is still detecting a flame even though it has tried to turn the fuel off, which requires an immediate inspection for safety.
Your boiler thinks it still sees a fire inside the burner even though it has commanded the system to turn off.
Your boiler has detected a potential internal gas leak within the valve system and has shut down for safety.
Your boiler has detected a potential internal fuel leak during its safety check, which prevents it from starting up to ensure your safety.
Your boiler is displaying a status code because the reset button was pressed accidentally or for too long.
Your boiler has lost its connection to the main electricity supply, which is preventing it from starting up or continuing to run.
Your boiler has detected that the water pressure is too low, which means it cannot provide heat or hot water properly until the system is topped up.
Your boiler is experiencing a critical control system error that causes it to shut down and attempt to restart itself repeatedly.
Your boiler is currently idle because your thermostat or timer hasn't told it to turn on for heating or hot water.
Your boiler is receiving a signal to provide heating and is currently operating exactly as it should.
Your boiler is overheating because the water inside it is heating up much more quickly than it can be moved around your radiators.
Your boiler has lost power and the display or indicator light is completely dark, meaning it cannot start the heating process.
Your boiler is currently performing a restart process after a fault has been detected or the reset button has been pressed.
Your boiler is currently testing if it can create a spark to light the burner as part of its normal startup process.
Your boiler's internal cooling or exhaust fan is not starting correctly, which means the system cannot safely begin the heating process.
Your boiler is performing a routine self-check on the internal pump to ensure water can circulate properly through the system.
Your boiler is having trouble directing heated water to the correct place, which usually means the internal valve that switches between heating and hot water has stuck during a self-test.
Your boiler's electronic control system is failing to correctly test its flame detection circuit, meaning the system cannot safely confirm if the fuel is burning.
BoilerFaultCodes