13 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Tap any card for details
Your boiler has lost the signal from the weather sensor outside your home and is now operating at a standard default setting.
Your boiler has lost the ability to accurately measure the temperature of the water leaving it, so it has safely shut itself down to prevent overheating.
Your boiler is struggling to accurately detect your hot water temperature because one of its internal sensors has stopped sending a signal.
Your boiler has detected that it is running too hot or that harmful exhaust fumes are not escaping properly, so it has automatically turned itself off to stay safe.
Your boiler has detected that the flame inside has gone out unexpectedly while it was trying to heat your water or home.
Your boiler is struggling to push air through the system correctly, which is preventing it from lighting safely.
Your boiler has detected an issue with the gas supply or an external safety switch, causing it to shut down to keep your home safe.
Your boiler is failing to light because it cannot detect a flame, meaning you currently have no heating or hot water.
Your boiler's internal computer is experiencing a communication fault, which has caused it to shut down for safety.
Your boiler is displaying this message because the reset button was pressed even though there was no actual problem for it to fix.
Your boiler's main control computer is experiencing a communication fault, which means the system has safely shut itself down to prevent operational errors.
Your boiler has stopped working because the mechanical fan responsible for venting combustion gases cannot reach the necessary speed to operate safely.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.
BoilerFaultCodes