11 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
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Your boiler's safety sensor is detecting a flame when there shouldn't be one, causing it to stop the ignition process for your safety.
Your boiler's reset button is being pressed or held for too long, or there is an electronic glitch preventing the system from restarting properly.
Your boiler has stopped working because its internal computer chip has suffered a permanent memory failure and can no longer control the heating process.
Your boiler has detected an unstable electrical supply, meaning the power entering the unit is either too high or too low for it to run safely.
Your boiler has tried to light several times without success and has now shut itself down as a safety precaution.
Your boiler has detected a flame when it shouldn't, causing it to shut down for safety to prevent oil from building up inside.
Your boiler has stopped working because of an internal electrical circuit failure involved in controlling the fuel supply.
Your boiler has stopped working because the internal fan, which safely clears waste gases, is either not spinning or has been disconnected.
Your boiler has detected an issue with the electrical power supply coming from the mains, meaning it cannot run safely or consistently.
Your boiler has stopped running because it failed to light the flame or detect that one was present.
Your boiler has failed to ignite the burner and has safely shut itself down to prevent a fuel build-up.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes