129 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
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Your boiler has reached the required temperature and is taking a normal break from firing while it waits for the water to cool slightly.
Your boiler has detected that it is getting too hot too quickly or that water isn't moving through the system properly.
Your boiler has become too hot and has automatically shut down into a safety mode to prevent damage.
Your boiler has temporarily lost its flame and is trying to restart itself, which might cause your heating or hot water to cut out briefly.
Your boiler has tried to light the flame several times without success, so it has shut down for safety.
Your boiler is having a temporary glitch in its internal computer system and is attempting to fix itself automatically.
Your boiler's fan, which safely pushes exhaust gases out of the flue, is not spinning correctly, causing the system to shut down for safety.
Your boiler has experienced a temporary electronic glitch in its settings and is currently trying to fix itself automatically.
Your boiler's internal memory chip has developed a communication fault, meaning the control board can no longer read its essential settings.
Your boiler has encountered a minor temporary glitch and is currently pausing before it attempts to restart itself automatically.
Your boiler has encountered a general communication error or internal glitch that is preventing it from running properly.
Your boiler's fan unit is not spinning correctly, which means the system cannot safely vent exhaust gases and has shut down as a precaution.
Your boiler has stopped working because the electrical supply from your home is too low to safely power the system.
Your boiler has switched itself off because it got too hot and needs to cool down and be reset.
Your boiler's internal computer has encountered a critical error and can no longer control the heating or hot water safely.
Your boiler's internal computer has developed a serious communication error and can no longer control the heating system safely.
Your boiler is struggling to move water around the system or has detected it is getting too hot too quickly without enough water inside.
Your boiler has detected a faulty temperature sensor, which means it cannot accurately measure how hot the water is and has stopped working for safety.
Your boiler has detected an electrical wiring issue where the power supply wires are connected in the wrong order.
Your boiler's main control computer has developed a fault and can no longer communicate with the rest of the system.
Your boiler has become too hot and has switched itself off to prevent damage.
Your boiler has too much water in the system, which puts extra stress on the internal components and causes it to shut down for safety.
Your boiler has detected that there is not enough water in the system to operate safely and has shut down as a precaution.
Your boiler has stopped working because the water pressure in the central heating system has dropped too low.
Your boiler has stopped working because water is not moving through the system properly, causing it to get too hot too quickly.
Your boiler has failed to heat the stored water to a high enough temperature to kill off any potential bacteria in the tank.
Your boiler started to heat up but the flame went out unexpectedly while it was running.
Your boiler has failed to light after several attempts, meaning it is not currently producing any heat or hot water.
Your boiler has been manually reset too many times and needs to be cleared by holding the selector switch in the 'R' position for a few seconds.
Your boiler has detected that the fan, which safely removes waste gases from your home, is not spinning at the correct speed or has stopped working.
Your boiler has detected a problem with how it moves air and waste gases through the system, preventing it from lighting safely.
Your boiler has detected a problem with how water is flowing or being measured, which is preventing it from heating up safely.
Your boiler has detected an issue with how it moves air and waste gases through the system, preventing it from firing up for safety.
Your boiler has detected that it is heating up without enough water circulating through the system, causing it to shut down to prevent overheating.
Your boiler has detected a problem with its electrical earthing connection, which prevents it from operating safely.
Your boiler has switched itself off because it has started to get too hot, usually because water isn't flowing through the system correctly.
Your boiler has stopped working because it cannot correctly measure the temperature of the water returning to the unit due to a faulty or disconnected sensor.
Your boiler has stopped working because it cannot correctly read the temperature of the water returning to the unit due to a sensor connection problem.
Your boiler has detected that the water coming back from your radiators is hotter than the water going out, which usually means the water isn't circulating through your heating system correctly.
Your boiler has tried to light several times but the flame keeps going out, so the system has locked itself for safety.
Your boiler has detected that the fan is not spinning at the correct speed to safely clear exhaust fumes, often caused by a strong gust of wind or a mechanical fault.
Your boiler has detected that the water coming back from your radiators is hotter than the water leaving the boiler, which usually means the water isn't circulating correctly.
Your boiler has stopped working because water is not moving around the system properly or a internal temperature sensor is failing to report correctly.
Your boiler has shut down because it is getting too hot inside, likely due to water not moving through the pipes correctly or a part failure.
Your boiler is simply notifying you that the reset button has been pressed and it is restarting itself.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler's internal electronics have encountered a communication failure or hardware fault that is preventing it from running safely.
Your boiler's main control board has lost connection with the gas supply system, meaning it cannot safely ignite to provide heat or hot water.
Your boiler’s internal control board has detected an incorrect configuration setting which is preventing it from running properly.
Your boiler's electronic control board has detected an incorrect internal setting, likely caused by a configuration pin being moved or failing.
Your boiler's electronic control board has detected an incorrect internal setting or a configuration mismatch.
Your boiler is having trouble communicating with an external control, such as your thermostat or timer, due to a likely wiring fault.
Your boiler is having trouble communicating with your thermostat or wireless control system.
Your boiler has lost communication with its gas control unit and cannot heat your water or radiators for safety reasons.
Your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit, usually due to a faulty sensor or a loose wire.
Your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit, leading to a complete shutdown for safety.
Your boiler has shut down because the water inside is getting too hot too quickly, usually because it isn't moving through the system properly.
Your boiler has stopped working because it has detected a problem with the sensor that monitors the temperature of the exhaust gases.
Your boiler has detected an issue with the sensor that monitors the temperature of the exhaust chimney, causing the system to shut down for safety.
Your boiler has shut down because it is getting too hot inside, which could be caused by a lack of water flow, a blockage in the chimney, or a faulty sensor.
Your boiler has overheated or detected that water is not moving through the system correctly, causing it to shut down for safety.
Your boiler has failed to ignite, meaning it is unable to create a flame to provide heating and hot water.
Your boiler's electronic safety system thinks a flame is burning when it shouldn't be, which has caused it to shut down for your safety.
Your boiler has detected that the internal fan, which safely clears exhaust fumes, is stuck or not spinning correctly.
Your boiler has detected a serious internal problem with how it manages gas and air for the burner, causing it to shut down for safety.
Your boiler's internal thermometer has stopped working correctly, meaning the system cannot safely monitor the water temperature to provide heating or hot water.
Your boiler has become too hot and has shut down as a safety precaution to prevent damage.
Your boiler is struggling to move water around the system, usually because air is trapped in your radiators or the pressure is too low.
Your boiler's internal computer has developed a fault and can no longer control the heating system safely.
Your boiler has failed to light, which could be due to air trapped in the system or a temporary interruption in your gas supply.
Your boiler has lost its connection to the gas control valve, meaning it cannot safely ignite to provide heating or hot water.
Your boiler has lost connection with a thermometer outside your home, which helps it adjust its temperature based on the weather.
Your boiler has detected that water is not circulating correctly through the system, preventing it from heating up safely.
Your boiler has detected that a internal water flow sensor is stuck in the 'on' position even when the pump is not running.
Your boiler has detected an internal electrical communication error with the gas control system, preventing it from lighting safely.
Your boiler has likely stopped heating your radiators because a temperature sensor responsible for the central heating has developed a fault.
Your boiler has detected a blockage in the exhaust pipe or a fault with its internal sensors, causing it to shut down for safety.
Your boiler has detected an issue with the sensor that monitors the temperature of the water returning from your radiators.
Your boiler's temperature sensor for hot water has stopped working correctly, meaning your boiler can no longer tell how hot your water is.
Your boiler is not burning gas correctly because something may be blocking the external exhaust pipe or the air intake.
Your boiler is having trouble detecting when you turn on your hot taps, which means your water may not heat up consistently or at all.
Your boiler’s internal computer needs to re-sync its gas and air settings to ensure it is burning fuel efficiently and safely.
Your boiler's internal computer has lost communication with the sensor that monitors water pressure, meaning it has stopped working as a safety precaution.
Your boiler's internal computer has lost contact with its control components, meaning it cannot receive the instructions needed to operate.
Your boiler has detected an error while trying to automatically adjust its internal settings to ensure the gas is burning correctly.
Your boiler has lost track of the current time or date due to a clock error inside its control centre, which may prevent your heating schedules from working correctly.
Your boiler is struggling to move water around the system effectively, which is causing it to stop running to prevent overheating.
Your boiler has switched itself off because it has reached an unsafe temperature, usually due to poor water circulation or a blockage.
Your boiler has too much water inside it, causing the internal pressure to rise above the safe operating limit.
Your boiler has stopped working because the water pressure inside the system is too low.
Your boiler has stopped working because the water pressure is too low and needs to be topped up.
Your boiler is struggling to move water around the system correctly, which could be due to a blockage, air bubbles, or a pump issue.
Your boiler has lost its flame multiple times during operation and has shut down as a safety precaution.
Your boiler is struggling to keep its flame steady while trying to set itself up, causing it to shut down for safety.
Your boiler has shut down because a sensor has detected that the exhaust gases are getting too hot, or the sensor itself has developed a fault.
Your boiler has switched itself off because it detected that the exhaust gases have become too hot, which is a safety measure to prevent damage.
Your boiler has stopped working because it cannot light a flame, which is usually caused by a gas supply issue or a frozen condensate pipe.
Your boiler is struggling to ignite because it cannot detect a flame or a steady gas supply despite trying to start several times.
Your boiler has stopped working because it cannot detect a steady flow of gas or is experiencing an internal electronic fault related to the gas valve.
Your boiler has noticed that water is not circulating correctly or the temperature readings are inconsistent, causing it to stop for safety.
Your boiler has stopped working because the fan that helps remove waste gases is failing or there is a communication problem between the fan and the control board.
Your boiler has detected a problem with the fan that clears out exhaust gases, meaning it cannot start up safely for heating or hot water.
Your boiler's temperature sensor for hot water has developed a fault, meaning the system cannot accurately measure or provide hot water.
Your boiler has detected an issue with the sensor that measures water pressure, which means it cannot tell if it is safe to keep running.
Your boiler's internal computer has developed an electronic fault and is struggling to communicate with the rest of the system.
Your boiler's internal computer has encountered a glitch or hardware failure and has shut down for safety.
Your boiler has detected that water is not circulating correctly through the system before the burner ignites, often due to an air lock or a blockage.
Your boiler has detected that water is not moving through the system properly, which is causing the unit to overheat or risk running dry.
Your boiler has detected an issue with the electrical power timing coming into the unit, which is preventing it from running safely.
Your boiler is having trouble measuring the temperature of your hot water, which usually means it cannot provide a consistent warm flow to your taps.
Your boiler thinks there is a flame present even though it hasn't actually started the ignition process.
Your boiler has detected that the electrical supply voltage is too low for it to operate safely and effectively.
Your boiler is checking if there is enough water pressure to run safely and may have paused temporarily.
Your boiler has stopped working because the internal control board cannot talk to the gas valve, meaning the system cannot safely ignite to provide heat or hot water.
Your boiler has detected that the water is heating up too quickly or isn't moving through the system properly, causing it to shut down to prevent overheating.
Your boiler is overheating or water isn't moving through the pipes fast enough, causing the system to shut down for safety.
Your boiler has detected that it is getting too hot too quickly, usually because water isn't moving through the system properly.
Your boiler is struggling to move water through the system, which is likely caused by low water pressure or a blockage.
Your boiler is heating up too quickly when you turn on the hot water, likely because water isn't flowing through the system as fast as it should.
Your boiler's main control board has lost its internal settings and does not know which model it is supposed to be operating.
Your boiler has hit a temporary software snag where it is confused about its internal setup and needs a simple reset to clear the error.
Your boiler's internal computer is having a temporary glitch with its settings and is struggling to understand its own configuration.
Your boiler has detected that the water pressure is too low for it to operate safely, which is usually caused by a small leak or the need to top up the system.
Your boiler is struggling to communicate with its internal temperature sensors, which is temporarily preventing it from heating your home or water.
Your boiler's internal computer is having trouble talking to its main control board, preventing the system from starting up.
Your boiler has lost its flame while it was running, meaning it can no longer heat your water or radiators.
Your boiler is not receiving any electricity and the display has completely shut down.
Your boiler has tried to light several times but has failed to stay on, so it has locked itself for safety.
Your boiler has detected an internal electrical communication problem between its main components.
BoilerFaultCodes