83 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
This boiler uses indicator light combinations
Note which lights are on, off, or flashing and at what speed. Match the combination to the cards below. Do not reset until you have noted the pattern. How to read fault codes →
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Your boiler has stopped working because it cannot light its internal flame to heat your water.
Your boiler has stopped working because it cannot light the flame required to produce heat or hot water.
Your boiler has stopped working because it is not receiving the necessary fuel, water, or power it needs to function.
Your boiler has failed to light the flame three times, so it has purposefully shut itself off for your safety.
Your boiler has sensed that it is getting dangerously hot and has shut itself down to prevent internal damage.
Your boiler has stored a record of a previous error that caused it to stop working, and it may need a professional to clear the history or investigate the underlying cause.
Your boiler is trying to ignite but cannot sense a flame, so it has safely shut down to prevent gas from escaping.
Your boiler has stopped working because it is having trouble reading the temperature of the water being sent to your radiators.
Your boiler is struggling to move hot water around the system effectively, which is causing it to overheat and shut itself down as a safety precaution.
Your boiler is failing to confirm that dangerous waste gases are being safely vented, so it has shut down to keep your home safe.
Your boiler has detected very cold temperatures and is running the water pump to prevent the pipes from freezing.
Your boiler is struggling to accurately measure the temperature of the water used for your radiators, causing it to stop heating your home as a safety precaution.
Your boiler has detected that the temperature is low enough to risk freezing and has automatically started its internal heating process to keep its pipes safe.
Your boiler is struggling to clear fumes properly, so it has safely shut down to prevent the risk of harmful gases entering your home.
Your boiler has detected that hot water isn't moving around your radiators or pipes properly, causing it to stop to prevent overheating.
Your boiler has stopped because the water pressure inside the system has dropped too low to operate safely.
Your boiler has lost the ability to measure the temperature of your hot water, which means it will stop providing hot water until the faulty sensor is replaced.
Your boiler has stopped producing hot water because a sensor that measures water temperature is providing an incorrect signal.
Your boiler has lost the ability to monitor the temperature of the water being sent to your radiators, so it has shut down as a precaution to prevent overheating.
Your boiler is currently trying to relight itself because it failed to catch a flame on the previous attempt.
Your boiler is having trouble communicating with its internal controls due to a connection issue, which is preventing it from firing up.
Your boiler has detected that the internal exhaust fan is not spinning fast enough to safely clear fumes, so it has shut down to prevent a safety risk.
Your boiler is unable to safely move air and exhaust gases, so it has shut down to prevent any risk of fumes entering your home.
Your boiler is failing to detect the temperature of your hot water cylinder, which means it will likely stop providing hot water until the faulty sensor is replaced.
Your boiler has detected that a temperature sensor is not communicating correctly, which may prevent your hot water or heating from working reliably.
Your boiler has stopped working because it cannot light the internal flame or keep it burning.
Your boiler has detected that it is running too hot and has automatically shut down to prevent any internal damage.
Your boiler has detected an issue with the ignition process and has shut down as a precaution to prevent unburnt gas from building up.
Your boiler has detected that hot water isn't moving through your heating system properly, so it has shut down to prevent itself from overheating.
Your boiler has detected an issue with the air intake or exhaust system, causing it to shut down to prevent unsafe operation.
Your boiler has detected an issue with the ignition process and has shut itself down to prevent unsafe gas buildup.
Your boiler has detected that it is running much hotter than it should be and has automatically switched itself off to prevent internal damage.
Your boiler has detected that the water inside it is getting too hot and has temporarily switched itself off to prevent any damage.
Your boiler has detected that the water pump inside is stuck or frozen, preventing it from circulating heat through your home.
Your boiler has detected a flame signal when it shouldn't be running, which indicates a potential internal problem with the gas safety detection system.
Your boiler is struggling to read the temperature of the water returning to it, so it has safely shut down to prevent overheating.
Your boiler is struggling to detect the temperature of the water for your taps and showers, so it has turned off the hot water to prevent any issues.
Your boiler is struggling to move water through its system, which prevents it from heating your home or water properly.
Your boiler has detected a faulty reading from the sensor that manages your hot water temperature.
Your boiler is struggling to clear exhaust fumes correctly because it is not detecting the necessary air pressure change to safely start the heating process.
Your boiler has detected that the internal fan is not switching on, which prevents it from safely clearing waste gases.
Your boiler has lost its connection to the sensor that monitors your hot water cylinder temperature, causing it to stop heating your water.
Your boiler is struggling to detect the temperature of the water stored in your hot water cylinder, which is preventing it from heating your water correctly.
Your boiler is struggling to switch between heating your radiators and providing hot water, meaning you likely have no hot water from your taps.
Your boiler has detected that water is not flowing through the system correctly, which is preventing it from heating your home safely.
Your boiler's temperature sensor is disconnected or faulty, meaning it cannot accurately measure how hot the water is to safely heat your radiators.
Your boiler is failing to light the flame safely, so it has purposefully shut down to prevent gas from building up.
Your boiler is struggling to switch between heating your radiators and providing hot water, meaning you may have issues getting a hot shower or heat in your home.
Your boiler is struggling to detect that air is flowing correctly to start the combustion process, preventing it from firing up.
Your boiler has detected that the water pump inside is stuck or not moving, usually because it has seized up during a period of inactivity.
Your boiler is failing to detect the temperature of your hot water cylinder, which prevents it from heating your water correctly.
Your boiler has lost the ability to detect the temperature of the water used for your taps and shower, so it has stopped providing hot water to ensure safety.
Your boiler has detected that it is running too hot and has automatically shut down to prevent damage to its internal parts.
Your boiler is failing to start because it cannot detect that the air fan is running and the water pressure may be incorrectly sensed.
Your boiler has detected that the water inside the system is not circulating properly, causing it to overheat and shut itself down for safety.
Your boiler is struggling to detect the temperature of the water in your separate hot water cylinder, which may result in a lack of hot water at your taps.
Your boiler has detected an internal sensor failure affecting the hot water supply, meaning it cannot accurately tell if the water is hot enough to use.
Your boiler has detected that it is getting too hot and has temporarily paused operating to prevent damage to its internal parts.
Your boiler has detected that the water temperature sensor is not providing a valid reading, causing the system to stop working as a safety precaution.
Your boiler is mistakenly detecting a flame when it shouldn't be, which is a safety lockout preventing it from firing up.
Your boiler has detected that water is not flowing properly around your heating system, so it has safely shut down to prevent overheating.
Your boiler's main control panel and its internal display screen are having trouble sending information back and forth, causing the system to stop functioning properly.
Your boiler's internal computer is unable to send information to its main controller, which prevents the unit from starting correctly.
Your boiler has detected that it is getting too hot and has temporarily paused its operation to prevent damage.
Your boiler is struggling to switch between heating your radiators and providing hot water, which may cause your taps to run cold or your heating to stay on constantly.
Your boiler is struggling to accurately detect the temperature of the water being sent to your hot water tank, causing the system to stop heating it properly.
Your boiler has lost the ability to measure the temperature of the water being stored for your taps, which prevents it from heating your hot water correctly.
Your boiler has failed to start its internal fan, which prevents it from safely igniting and providing heating or hot water.
Your boiler is failing to start because it cannot confirm that the internal air pressure system is working correctly.
Your boiler is failing to start because it cannot confirm that the internal fan is effectively clearing out used gases before ignition.
Your boiler is not detecting enough water flowing through its internal heating system to operate safely.
Your boiler is struggling to detect the temperature of the water flowing into it, so it has safely shut down to prevent overheating.
Your boiler is experiencing a communication error with its hot water temperature sensor, which is preventing it from providing hot water correctly.
Your boiler is failing to detect the temperature of the water entering the system, which is preventing it from heating your home safely.
Your boiler is struggling to detect the temperature of your hot water supply because a connection or sensor inside has likely stopped working.
Your boiler has detected a failure in the internal electronic control system, preventing it from operating safely.
Your boiler has detected an issue with the circuit board's ability to communicate with the system sensors, causing it to stop operating to ensure safety.
Your boiler has detected an issue with the air supply or exhaust gases, meaning it has safely shut down to prevent unsafe operation.
Your boiler has detected an issue with the airflow system, which means it cannot safely flue away exhaust gases and has shut down to protect your home.
Your boiler has detected a failure in the internal electronic control board, preventing it from operating correctly.
Your boiler has detected a problem with the internal water circulation system, which is preventing it from heating your home or water safely.
Your boiler has detected a communication error between its internal electronic control systems, causing the system to stop operating.
Your heating system is struggling due to trapped air or low water pressure, which is causing the banging or whooshing noises you are hearing.
BoilerFaultCodes