12 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Greenstar i
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 has automatically turned itself off because the exhaust area is getting too hot, indicating a potential blockage or a problem with how the gases are clearing.
Your boiler has detected a critical internal error that caused it to shut down for safety reasons and will not restart on its own.
Your boiler has detected a critical internal error and has safely shut itself down to prevent damage, meaning you currently have no heating or hot water.
Your boiler's internal computer has developed a fault and can no longer safely control the heating or hot water functions.
Your boiler has detected a critical internal error and purposefully shut itself down to prevent damage, meaning you currently have no heating or hot water.
Your boiler has detected that the exhaust gases are getting too hot and has shut down as a safety precaution to prevent damage.
Your boiler has lost its digital connection to the wireless thermostat or timer controller, meaning it no longer knows when to turn your heating on or off.
Your boiler is failing to ignite because it is not receiving enough gas, or its waste pipe or exhaust flue is blocked, meaning it cannot operate safely.
Your boiler's electronic brain is missing a crucial identification chip that tells it how to operate, so it has safely shut itself down until the part is properly installed.
Your boiler has detected that the burner is still trying to stay lit even though it should have turned off, which suggests a potential issue with how it manages the fuel supply.
Your boiler has completely lost power and is not showing any lights or signs of life.
Your boiler has lost all power and is completely unresponsive, meaning it is currently unable to provide any heating or hot water.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes