7 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Greenstar 15i System ErP
This boiler uses indicator light combinations
Note which lights are on, off, or flashing and at what speed. Match the combination to the cards below. Do not reset until you have noted the pattern. How to read fault codes →
Tap any card for details
Your boiler has stopped working because it cannot properly move the air and fumes required for safe operation.
Your boiler has detected that it is getting dangerously hot and has shut itself down to prevent damage or fire risks.
Your boiler is failing to light the flame needed to heat your home, so it has locked itself for safety and requires a manual reset.
Your boiler's internal computer is malfunctioning, meaning the system has stopped working entirely to prevent further issues.
Your boiler is failing to light the flame, so it has safely shut itself down to prevent a gas leak.
Your boiler has stopped working because it cannot light its internal flame, which means your heating and hot water have switched off for safety.
Your boiler has detected an internal error and has safely shut itself down to prevent damage, meaning your heating and hot water will not work until it is reset or repaired.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes