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 →
Tap any card for details
Your boiler has reached its set temperature and is temporarily pausing until the water cools down enough to restart.
Your boiler has likely stopped heating because it is struggling to circulate water properly or a internal temperature sensor has failed.
Your boiler has got too hot and has shut itself down as a safety precaution.
Your boiler has temporarily lost its flame and is currently trying to restart itself automatically.
Your boiler has tried to light the flame several times but has been unable to start, leaving you without heating and hot water.
Your boiler is temporarily failing to talk to its internal computer, but it should fix itself automatically in a few moments.
Your boiler's fan is not running or communicating correctly, preventing the system from safely clearing away exhaust fumes and starting the ignition process.
Your boiler has experienced a temporary software glitch with its internal settings and will automatically try to fix itself.
Your boiler's internal memory chip has developed a communication fault, preventing the system from running safely.
Your boiler has encountered a minor glitch and is currently pausing briefly before attempting to restart itself automatically.
Your boiler has encountered an internal timing or communication problem that is preventing it from running properly.
Your boiler's fan, which safely pushes exhaust gases outside, is not working correctly, causing the system to shut down for safety.
Your boiler has detected that the electricity supply coming into your home is too weak for it to run safely.
Your boiler has got too hot and has shut itself down as a safety precaution to prevent damage.
Your boiler's internal computer has encountered a critical communication error and cannot control the heating process safely.
Your boiler's internal computer has developed a fault and can no longer control the heating system safely.
Your boiler has detected that water isn't moving through the system properly or there isn't enough water inside the unit to operate safely.
Your boiler has detected a faulty internal temperature sensor, which means it cannot safely monitor how hot the water is and has stopped working as a precaution.
Your boiler has detected that the electrical wiring coming from your home's power supply is connected the wrong way around.
Your boiler's internal computer has encountered a critical electronic failure and can no longer control the heating process.
Your boiler has got too hot and has shut itself down as a safety precaution to prevent damage.
Your boiler has too much water in the system, which puts unnecessary strain on its internal components.
Your boiler has stopped working because the water pressure is too low, often caused by a small leak or air in the radiators.
Your boiler has stopped working because the water pressure in the system has dropped too low and needs topping up.
Your boiler has stopped working because water is not moving around the system properly, causing it to overheat and shut down for safety.
Your boiler has failed to heat the hot water tank to a high enough temperature to kill off bacteria, which is a standard safety routine.
Your boiler started to heat up but the flame went out unexpectedly while it was running.
Your boiler has failed to light the gas burner after several attempts, meaning your heating and hot water will not work.
Your boiler has gone into a safety lockdown because the reset button has been pressed for too long or too many times in a short period.
Your boiler's fan is not running at the correct speed or has stopped working, which means it cannot safely clear waste gases and has shut down as a precaution.
Your boiler is having trouble clearing away exhaust fumes or pulling in fresh air, so it has shut down for safety.
Your boiler has detected a problem with how it monitors water pressure or flow, which is preventing the system from heating up correctly.
Your boiler has detected an issue with the air flow or ventilation, causing it to shut down for safety.
Your boiler has detected that it is heating up too quickly because there isn't enough water circulating inside it to carry the heat away.
Your boiler has lost its connection to the electrical earth, which is a safety feature that prevents electrical faults.
Your boiler has shut down because its internal temperature got too high, usually because water isn't moving through the system properly.
Your boiler has lost communication with its internal temperature sensor, preventing it from safely monitoring the water returning to the unit.
Your boiler has detected a problem with the sensor that monitors water returning to the unit, preventing it from heating your home safely.
Your boiler has detected that the water coming back from your radiators is hotter than the water leaving the unit, which usually means the water is flowing in the wrong direction or a sensor is misreading.
Your boiler is repeatedly failing to keep the flame lit while it is running, causing it to shut down for safety.
Your boiler's 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 sensed that the water returning from your radiators is hotter than the water leaving the boiler, which usually means there is a temporary circulation issue or a sensor mix-up.
Your boiler has stopped working because water is not moving through the system properly or a temperature sensor is disconnected.
Your boiler has shut down because it is getting too hot, likely due to water not flowing through the system properly or a faulty sensor.
Your boiler is simply letting you know that the reset button has been held down or activated.
Your boiler has stopped working because there is not enough water pressure in the system to operate safely.
Your boiler's main internal computer has suffered a communication failure or electrical damage, meaning it can no longer control the heating functions.
Your boiler's internal computer has lost contact with the gas control system, preventing the boiler from firing up for heating or hot water.
Your boiler's electronic control board has detected a configuration setting change that is preventing it from running correctly.
Your boiler's internal settings have been adjusted or moved, causing the control system to become confused about how the unit should operate.
Your boiler's internal computer settings have been changed or are set incorrectly, meaning the control board doesn't know how to operate the boiler properly.
Your boiler is having trouble communicating with external controls like your thermostat or timer due to a wiring issue.
Your boiler is having trouble communicating with your external thermostat or smart home controller.
Your boiler has lost its connection to the component that controls the fuel supply, meaning it cannot safely light the flame to provide heat or hot water.
Your boiler has lost track of the water temperature because a internal sensor cable has broken or failed, preventing the system from heating up safely.
Your boiler has stopped working because it cannot accurately measure the temperature of the water leaving the unit, leading to a complete shutdown for safety.
Your boiler has reached a dangerously high temperature and shut itself down because water is not moving through the system properly.
Your boiler has detected an issue with the sensor that monitors exhaust gases, causing it to shut down for safety.
Your boiler has detected an issue with the sensor that monitors exhaust gas temperatures, causing the system to shut down for safety.
Your boiler has shut down because it is getting too hot inside, likely due to a lack of water flow or a sensors detecting unsafe temperatures.
Your boiler has likely overheated or water is not circulating through the system properly, causing it to shut down for safety.
Your boiler is not receiving enough gas or cannot ignite the burner to provide heating and hot water.
Your boiler thinks a flame is present even when it should be off, causing it to shut down for safety precautions.
Your boiler has detected that the internal fan, which safely removes waste gases, has stopped spinning or cannot communicate with the main system.
Your boiler has detected a serious internal problem with the system that manages the gas flow and air mixture, causing it to shut down for safety.
Your boiler has detected an issue with the sensor that monitors internal water temperature, preventing it from heating up correctly.
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 a valve is closed.
Your boiler's internal computer has encountered a critical error and can no longer control the heating system safely.
Your boiler has tried to light several times but cannot start, meaning you currently have no heating or hot water.
Your boiler has detected a communication problem with its internal gas control system, meaning it cannot safely ignite to provide heating or hot water.
Your boiler has lost connection with its outside temperature sensor, which helps it decide how hard it needs to work 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 thinks water is still moving through the system even though the pump has stopped, which is preventing it from starting a new cycle safely.
Your boiler has detected an internal electrical communication error with the gas control system and has shut down for safety.
Your boiler's internal temperature sensor has stopped working correctly, which prevents the system from knowing when to safely heat your home.
Your boiler has detected a problem with how it disposes of waste gases or a blocked drainage pipe, causing it to shut down for safety.
Your boiler has detected an issue with the sensor that monitors the water temperature returning from your radiators, preventing the system from heating your home safely.
Your boiler's hot water sensor has detected a fault, meaning your taps might not provide hot water or the temperature could be inconsistent.
Your boiler is not burning gas correctly because something is likely blocking the external exhaust pipe or the air supply.
Your boiler is struggling to detect when you turn on a hot tap, meaning you might have inconsistent or no hot water.
Your boiler’s internal computer has lost its tuning settings and needs to be re-calibrated to burn gas safely and efficiently.
Your boiler's internal sensor is struggling to accurately measure the water pressure, which prevents the system from operating correctly.
Your boiler's internal computer has lost its connection with the main control board, meaning the parts aren't talking to each other properly.
Your boiler has detected an issue with the air and gas mixture while trying to automatically tune itself for safe operation.
Your boiler has lost track of the current time or date due to a technical error on its internal control board.
Your boiler is struggling to move heated water through the pipes and radiators, causing it to shut down to prevent overheating.
Your boiler has overheated, prompting a safety sensor to shut it down to prevent damage.
Your boiler has too much water in the system, which has caused the pressure to rise above the safe operating limit.
Your boiler has stopped working because the water pressure in the system has dropped too low and needs to be topped up.
Your boiler has stopped working because the water pressure is too low for the system to run safely.
Your boiler has detected that hot water isn't moving through the system properly, which is usually caused by a pump failure or a blockage.
Your boiler is struggling to keep its internal flame lit and has shut itself down after several failed attempts to stay running.
Your boiler is struggling to keep a steady flame while trying to automatically adjust its settings, 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 failed.
Your boiler has shut down because the exhaust gases have become too hot, which is a safety feature to prevent damage to the flue system.
Your boiler has tried to ignite but failed, which means the gas isn't reaching the burner or the flame isn't being detected.
Your boiler is failing to light because it cannot detect a flame despite trying to open the gas supply multiple times.
Your boiler has lost its gas supply due to an internal system fault, meaning it cannot light the flame to provide heating or hot water.
Your boiler has detected that water is circulting too slowly or getting too hot too quickly, causing it to shut down to prevent damage.
Your boiler has detected that the fan, which safely removes waste gases from your home, is not spinning correctly or has lost its electrical connection.
Your boiler has stopped working because the internal fan, which safely pushes exhaust fumes out of the flue, is not spinning at the correct speed or has failed.
Your boiler's hot water sensor has failed or has a bad connection, meaning the system cannot accurately measure the temperature of the water coming out of your taps.
Your boiler has detected an issue with the sensor that monitors water pressure, meaning it cannot accurately tell if there is enough water to run safely.
Your boiler's internal computer has encountered a software or communication error and cannot operate the heating or hot water safely.
Your boiler's internal computer has encountered an error and has shut itself down as a safety precaution.
Your boiler has detected that the water is not flowing around the system correctly before it tries to ignite, causing it to shut down for safety.
Your boiler has detected that water isn't moving through the system properly, which is causing the unit to overheat or run without enough water.
Your boiler has detected that the electricity coming from your home supply is at the wrong frequency, causing it to shut down for safety.
Your boiler's hot water sensor has failed or detected an error, meaning the system cannot accurately measure the temperature of the water coming out of your taps.
Your boiler thinks a flame is present even when it should be off, causing it to shut down for safety.
Your boiler is struggling to operate because it is not receiving enough electrical power from your home's mains supply.
Your boiler is performing a temporary check to ensure there is enough water pressure to operate safely.
Your boiler has lost the internal connection to its gas supply control, meaning it cannot provide heating or hot water until the communication is restored.
Your boiler is struggling to move water around the system properly, causing it to overheat and shut down for safety.
Your boiler is heating up too quickly or water isn't moving through the system properly, causing it to shut down to prevent overheating.
Your boiler has detected that it is getting too hot too quickly, usually because water isn't moving through the system fast enough to cool it down.
Your boiler is struggling to move water through the system, which is preventing it from heating up correctly.
Your boiler is heating up too quickly when you turn on the hot water, likely because the water isn't flowing through the system fast enough.
Your boiler's internal computer has forgotten its identity or hasn't been set up correctly, meaning it doesn't know how to operate your specific heating system.
Your boiler's internal computer is having a temporary disagreement with its saved settings and needs a quick reset to find its way again.
Your boiler's computer brain is momentarily confused by some internal settings and may need a simple electronic reboot.
Your boiler has detected that the water pressure is too low or unstable, which is preventing it from heating your home safely.
Your boiler has stopped working because of a temporary communication problem between its internal sensors and the main control board.
Your boiler's internal computer is having trouble talking to its main control board, which has caused the system to stop working for safety.
Your boiler has lost its flame while it was running, which means it cannot heat your water or radiators and has shut down for safety.
Your boiler is not receiving any electricity and has completely shut down.
Your boiler has tried to light several times but cannot establish a steady flame, causing it to shut down for safety.
Your boiler has detected an internal communication problem between its electronic components, meaning it cannot operate safely.
BoilerFaultCodes