26 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler is trying to start up but cannot successfully light the internal flame to produce heat.
Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage.
Your boiler has detected that the exhaust gases are becoming dangerously hot and has shut itself down to prevent damage or overheating.
Your boiler has detected an issue with the electrical connection to the internal gas control system, meaning it cannot safely start up to provide heat or hot water.
Your boiler has stopped working because it cannot correctly measure the temperature of the water flowing through your heating system.
Your boiler is having trouble measuring the temperature of your hot water, which means it has stopped providing hot water to your taps and shower.
Your boiler has been manually restarted too many times due to an unresolved issue and has now locked itself for safety.
Your boiler has stopped working because the water pressure inside your heating system has dropped too low.
Your boiler is struggling to detect the temperature of your hot water cylinder, which means it may fail to heat your taps or shower correctly.
Your boiler has detected an internal communication or connection error within its control system, preventing it from operating safely.
Your boiler has stopped working because it cannot communicate with the inner fan that clears waste gases, meaning the appliance has safely shut down to prevent unsafe operation.
Your boiler is confused because it senses a flame inside when it shouldn't be there, or it detects a flame when it has not yet commanded the gas to turn on.
Your boiler's control panel detects that one of the buttons is jammed or sticking, preventing it from functioning correctly.
Your boiler has detected that it is heating up significantly faster than it should, so it has safely shut itself down to prevent damage.
Your boiler is struggling to circulate water properly, causing the system to overheat almost instantly, which means it has shut down to protect itself from damage.
Your boiler has detected that a temperature sensor inside the exhaust system is not giving a proper reading, so it has shut down to keep you safe.
Your boiler has lost its digital connection to the wall-mounted thermostat control, meaning it doesn't know when to turn your heating on or off.
Your boiler is failing to start because it is not receiving enough electrical power from your home's mains supply.
Your boiler is struggling to keep its flame lit, so it is automatically turning itself off and trying to restart to keep you safe.
Your boiler is struggling to keep its internal flame lit while it is running, so it has safely shut down to prevent any issues.
Your boiler has failed to start after multiple attempts and has locked itself down for safety to prevent gas build-up.
Your boiler has lost its connection to the weather sensor that sits on the outside wall of your home, meaning it doesn't know how cold it is outside to adjust your heating automatically.
Your boiler has detected that the exhaust gases are getting too hot and has automatically lowered its power to prevent overheating and potential damage.
Your boiler has lost its wireless connection to the temperature controller, meaning it doesn't know when to turn your heating on or off.
Your boiler has detected that the exhaust gases are becoming too hot, so it has safely shut itself down to prevent damage.
Your boiler is trying to start but the flame is not staying lit, so it has safely shut down to prevent gas from building up.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes