43 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler's electronic display and control panel are failing to communicate correctly, which means you cannot currently adjust or monitor your heating settings.
Your boiler has lost the ability to accurately measure the temperature of the water circulating through your heating system, so it has shut down to prevent damage.
Your boiler has stopped working because a sensor that monitors the temperature of the water returning to the system is reading incorrectly or has disconnected.
Your boiler has failed to light the flame needed to provide heating or hot water, and it has now locked itself out for safety.
Your boiler's temperature sensor is providing faulty readings, so it has safely shut down to prevent overheating.
Your boiler is struggling to accurately measure the temperature of the water returning to it, so it has stopped working to prevent potential overheating.
Your boiler has detected that it is running too hot and has automatically shut down to prevent damage to its internal components.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler has shut down because the water leaving the boiler is getting much hotter than the water returning, usually pointing to a blockage or a pump issue.
Your boiler is struggling to pump water around your heating system correctly, which is likely due to low system pressure or a blockage.
Your boiler has detected a problem with the internal part that controls the flow of gas, which is preventing it from lighting safely.
Your boiler has stopped working because it cannot confirm that the flame is staying lit safely.
Your boiler is not receiving enough gas or cannot create a flame to start the heating process.
Your boiler was working but the flame has unexpectedly gone out, causing the system to stop for safety.
Your boiler is struggling to push air through its exhaust system, which prevents it from firing up safely to provide heating or hot water.
Your boiler is struggling to communicate with its internal controls or external thermostat due to an electrical connection issue.
Your boiler has detected an issue with the electrical signal sent to the gas valve, meaning it cannot safely control the gas supply and has stopped working.
Your boiler has detected an issue with the valve that controls the gas supply and has safely shut itself down to prevent any risk.
Your boiler's computer is having trouble reading its internal software, which has caused it to stop working completely to prevent further errors.
Your boiler's internal computer has encountered a serious internal error and can no longer control the system, meaning your heating and hot water will not work.
Your boiler has detected that its internal control electronics are overheating and has shut itself down to prevent damage.
Your boiler is failing to detect the flame correctly, so it has safely shut itself down to prevent any risk.
Your boiler is struggling to keep a steady flame lit, often leading it to cut out for safety.
Your boiler's control panel and its internal computer are not communicating correctly, meaning the boiler has stopped working to prevent errors.
Your boiler is struggling to accurately measure the temperature of the water flowing into your radiators, so it has shut down to prevent overheating.
Your boiler has detected an inconsistent temperature reading between the water leaving the boiler and the water returning to it.
Your boiler is struggling to accurately measure the water pressure inside the system, which is preventing it from heating your home safely.
Your boiler is struggling to accurately measure the water pressure inside the system, which is preventing it from safely heating your home.
Your boiler has detected a safety-related issue with its internal heat protection circuit and has shut itself down to prevent potential damage or overheating.
Your boiler has detected an issue with the valve that regulates the gas supply, meaning it cannot safely ignite to provide heating or hot water.
Your boiler has detected that there is not enough water circulating inside the system to carry the heat away, so it has shut down to prevent damage.
Your boiler has detected an unusual and lasting temperature difference between the water leaving it and the water returning to it, so it has safely shut down to prevent damage.
Your boiler is struggling to compare the temperature of the water leaving and returning, meaning it has switched itself off to prevent overheating.
Your boiler has stopped running because it has detected a problem with the safety switch protecting your underfloor heating system.
Your boiler is temporarily running at maximum power for your central heating, which is usually just an informational status message rather than a breakdown.
Your boiler is temporarily running at ignition power to safely start up, which is usually a normal operational phase rather than a fault.
Your boiler is temporarily running at maximum heating power to test or calibrate its performance, which is usually a normal operational state rather than a fault.
Your boiler is currently in the process of automatically or manually filling its internal water system.
Your boiler is currently running a special programme to remove trapped air from the system after being filled or serviced.
Your boiler is running an automated air purge cycle to remove trapped air from the system after filling or servicing.
Your boiler has detected that the safety switch for your underfloor heating system is currently turned off or disconnected, so it has stopped heating that area.
Your boiler is simply indicating that it has successfully received a signal to turn on the central heating and is preparing to warm your home.
Your boiler has detected that the water pressure inside the system has become too high, which may prevent it from operating correctly.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes