26 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Greenstar i Junior
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 is attempting to light but failing to keep a flame, which means it cannot produce hot water or heating.
Your boiler has stopped working because it cannot light the internal flame or maintain it, meaning you currently have no heating or hot water.
Your boiler has stopped working because it cannot light the internal flame needed to heat your water.
Your boiler is failing to start safely, so it has locked itself to prevent any issues while it is unable to ignite properly.
Your boiler has stopped working because it failed to light or stay lit, so it has purposefully shut itself down for safety.
Your boiler has detected very cold temperatures nearby and has turned itself on to heat up its internal components and prevent your pipes from freezing.
Your boiler is currently protecting itself from freezing by running in a special cold-weather mode, or the status light on your display has broken.
Your boiler has stopped working for safety reasons and requires a manual reset to attempt to start again.
Your boiler is correctly telling you that it has already reached the temperature you asked for and is simply waiting for the water to cool down before heating it up again.
Your boiler has lost all power and is completely unresponsive to your heating controls.
Your boiler is receiving a signal to turn on but is failing to initiate the heating process, indicating a breakdown in communication between your thermostat and the boiler's internal controls.
Your boiler is not firing up correctly to provide heat because it is failing to receive a clear signal from your thermostat or controls.
Your boiler has stopped working completely and has entered a safety 'lockout' mode, meaning it needs a manual reset or a professional assessment to restart safely.
Your boiler has detected an internal failure and has safely shut itself down to prevent damage, meaning you currently have no heating or hot water.
Your boiler is experiencing a general operational issue because it cannot maintain the correct water temperature, preventing it from working reliably.
Your boiler has stopped working because it cannot detect a flame, so it has purposefully shut down to prevent gas from building up inside your home.
Your boiler has detected that it is getting too hot and has automatically shut down for safety to prevent damage.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.
Your boiler has reached an unsafe temperature and has automatically switched itself off to prevent damage.
Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage.
Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.
Your boiler has completely lost power, meaning it cannot switch on to provide heating or hot water.
Your boiler has lost all power and is completely unresponsive, meaning it cannot provide heating or hot water until the electrical supply is restored.
Your boiler is struggling to control its internal temperature correctly, causing it to shut down to prevent overheating or inefficient operation.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent any damage to the internal parts.
BoilerFaultCodes