70 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has detected that it is overheating and has automatically switched itself off to prevent damage.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler has detected that the water pressure in your heating system is too high for it to operate safely.
Your boiler has lost the ability to monitor the temperature of your hot water supply, meaning it will likely stop producing hot water until the faulty sensor is replaced.
Your boiler has stopped working because it is unable to accurately measure the temperature of the water used for your heating system.
Your boiler has detected a serious internal fault and has automatically shut itself down for safety reasons, meaning you currently have no heating or hot water.
Your boiler has detected that the water pressure inside the system is too low, preventing it from heating your home or water properly.
Your boiler is failing to light because it cannot detect a flame, meaning you currently have no heating or hot water.
Your boiler is struggling to push water around the system, which is preventing it from providing heating or hot water.
Your boiler has detected an issue with a secondary temperature sensor, which is preventing it from operating correctly.
Your boiler has detected that the flue gases are getting too hot, so it has safely shut itself down to prevent potential overheating or dangerous exhaust issues.
Your boiler has detected a potential issue with the ventilation system that clears away exhaust gases, so it has safely shut itself down to prevent any risk.
Your boiler is unable to safely move air through its system to burn gas properly, so it has shut down to prevent any unsafe operation.
Your boiler has detected that the water temperature in one of your heating circuits has become dangerously high and has automatically shut down to prevent damage.
Your boiler has lost the signal from a sensor responsible for monitoring the temperature of the water heading to your radiators, meaning it cannot accurately manage your heating.
Your boiler has detected that a secondary heating circuit, such as underfloor heating, has become too hot and has automatically shut down for safety.
Your boiler is having trouble communicating with the secondary heating zone, which means a specific part of your home may not be receiving heat as requested.
Your boiler has lost the connection to the temperature sensor responsible for reading your solar water heating panel, which may cause your solar system to stop working temporarily.
Your boiler is having trouble communicating with the temperature sensor linked to your solar water heating system, which may prevent the solar panel integration from working correctly.
Your boiler is having trouble reading the temperature from your solar water heating system, which means it may not be able to use solar energy to warm your water right now.
Your boiler's electronic control system is misconfigured to expect a solar water heating setup that is not actually connected or properly recognised.
Your boiler has detected an issue with how its internal settings or electronic controls are communicating, which is preventing it from operating correctly.
Your boiler's internal computer system is struggling to communicate with its electrical components, meaning it cannot reliably operate your heating or hot water.
Your boiler has shut down because it detected that dangerous exhaust fumes are not being cleared away safely through the chimney or flue.
Your boiler has stopped working because the water level inside the system is too low and needs to be topped up.
Your boiler has too much water pressure in the system, which causes it to shut down for safety.
Your boiler's temperature sensor for hot water has stopped working correctly, meaning your taps and showers may run cold or at inconsistent temperatures.
Your boiler has detected a problem with the internal temperature sensor that monitors the water leaving the boiler, which prevents it from heating up safely.
Your boiler has failed to light the flame, which means you will have no heating or hot water until the issue is resolved.
Your boiler has overheated, causing a safety sensor to automatically shut the system down to prevent damage.
Your boiler is struggling to detect a flame, meaning it cannot stay alight and providing you with no heating or hot water.
Your boiler has stopped working because water is not moving through the system properly, which is preventing it from heating up safely.
Your boiler has detected an issue with an internal sensor or a settings mismatch that is preventing it from running properly.
Your boiler is unable to control its gas supply correctly because an internal electrical connection to the gas valve has come loose or failed.
Your boiler's computer has been set to the wrong internal setting and doesn't know whether it is a room-sealed or open-vented unit.
Your boiler has shut down because the sensor that monitors exhaust gases has detected an unsafe temperature or has failed.
Your boiler has detected an issue with the sensor that monitors exhaust gases, and it has shut down as a safety precaution.
Your boiler has stopped working because the internal fan, which safely exhausts fumes, isn't communicating correctly with the main control board.
Your boiler has detected that its two internal temperature sensors are giving very different readings, suggesting a conflict in how it measures heat.
Your boiler has detected that the water drain for condensation is blocked or full, causing the system to shut down for safety.
Your boiler has been manually reset too many times in a short period and has temporarily locked itself for safety reasons.
Your boiler has detected a problem with the sensor that monitors water temperature returning to the unit, causing the system to shut down as a safety precaution.
Your boiler has detected that the electricity supply coming into your home is too weak for it to operate safely.
Your boiler has detected a problem with the safety circuit responsible for ensuring waste gases are being safely exhausted from the flue.
Your boiler has detected an issue with the electrical power coming from the grid, meaning the electricity frequency is not stable enough for it to run safely.
Your boiler has failed to stay lit despite several attempts and has shut down for safety.
Your boiler's control panel has detected that one of the buttons is stuck or the main control board is malfunctioning, preventing you from changing settings.
Your boiler is having trouble communicating with your external thermostat or smart home heating control.
Your boiler is failing to light because the internal computer and the gas valve are not communicating correctly to create a flame.
Your boiler has detected that the water is getting too hot too quickly, usually because the water isn't circulating through the system properly.
Your boiler has detected an issue with the water temperature flow and needs to run a self-test to recalibrate its internal sensors.
Your boiler has detected that a temperature sensor isn't sitting correctly on the main internal pipe, which means it can't accurately monitor the water getting sent to your taps or radiators.
Your boiler has detected a problem with one of the internal temperature sensors used to monitor the water flow, which is preventing it from heating correctly.
Your boiler has detected an electrical issue with its internal gas control system, preventing it from safely managing the fuel flow.
Your boiler has detected an internal electrical fault with the gas valve control system, which prevents it from safely managing the fuel flow.
Your boiler has detected an electrical issue with the gas control valve, meaning it cannot safely regulate the fuel needed to stay alight.
Your boiler has detected an internal communication problem between its main control board and the gas valve, meaning it cannot safely manage the fuel supply to stay lit.
Your boiler has detected a problem with how it is burning gas during the ignition process, which is often caused by an air or exhaust blockage.
Your boiler has shut down because it has struggled to stay lit or maintain a stable flame several times in a row.
Your boiler is struggling to burn gas correctly, often because of air in the pipes or a blockage in the chimney.
Your boiler has detected that the gas pressure coming from the mains is too low to operate safely and effectively.
Your boiler's internal computer has detected a serious electronic fault and has shut down to protect its circuits.
Your boiler is struggling to maintain a steady flame because it cannot properly detect or regulate the combustion process.
Your boiler is struggling to burn gas correctly and has shut down as a safety precaution.
Your boiler is struggling to get the right mix of gas and air for a safe flame, causing the system to shut down for safety.
Your boiler is struggling to maintain a stable flame or reach the required heat output, meaning it cannot provide heating or hot water safely.
Your boiler is struggling to keep a steady flame alight, causing the system to stop as a safety precaution.
Your boiler has shut down because it cannot safely expel exhaust fumes out of the external flue pipe.
Your boiler's internal computer has encountered a software error while trying to start up and cannot function.
Your boiler's internal computer has suffered a serious electronic failure and can no longer control the heating or hot water safely.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes