16 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Pick the one you have. The fault codes, GC numbers and manual differ by type.
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 stopped working because it is not receiving a reliable gas supply or cannot keep its internal pilot flame lit.
Your boiler has detected an internal communication error between its main electrical parts and has shut down as a safety precaution.
Your boiler has detected an internal communication error and has safely shut itself down to prevent further damage.
Your boiler has detected an internal communication error between its main electrical parts and has shut down as a safety precaution.
Your boiler is trying to start but the flame is cutting out shortly after ignition, meaning it cannot reliably heat your home or water.
Your boiler has sensed that the water inside it has become too hot 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 to operate safely.
Your boiler is struggling to move water around your heating system correctly, which is causing it to turn itself off to prevent overheating.
Your boiler has stopped because the flame inside has gone out and it cannot get it to stay lit.
Your boiler has detected that the water inside is not circulating correctly or the temperature sensor is misreading, which has caused it to shut down for safety.
Your boiler is failing to light because it cannot detect a flame, meaning you currently have no heating or hot water.
Your boiler has stopped working because it cannot light the internal flame to provide heat or hot water.
Your boiler has stopped working because it cannot light the gas flame needed to produce heat or hot water.
Your boiler has detected an internal communication error and has safely shut down to prevent further issues.
Your boiler has detected a communication error between its internal parts and has stopped working to prevent further damage.
Your boiler has stopped working because it cannot detect a flame or is not receiving the gas supply it needs to stay lit.
Not faults — these are normal operating states. Tap to expand.
Monthly cover means no unexpected bills when your boiler breaks down.
Affiliate links. We may earn a commission at no extra cost to you.
BoilerFaultCodes