17 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 41-149-02 | System 18 | 2008–present |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
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Your boiler has detected a flame signal even though it is trying to turn off, which is a safety concern that prevents the system from operating.
Your boiler has stopped working because it cannot light the flame and is detecting a fault with one of its internal heat sensors.
Your boiler has stopped working because it cannot detect a flame or a heat sensor in the exhaust pipe has failed.
Your boiler has stopped working because one of its internal temperature sensors has broken or is sending an incorrect reading, preventing the system from firing up.
Your boiler is failing to light the fuel needed to create heat, likely due to a problem with the internal gas control system.
Your boiler has identified a communication problem with the fan, which means it cannot safely start the burner to provide heat or hot water.
Your boiler has failed to light a flame because it isn't receiving the necessary electricity or gas supply to start up.
Your boiler's internal computer is having a communication error or failing to detect a flame, often caused by an incorrect configuration chip.
Your boiler's internal computer brain cannot communicate with its plug-in configuration chip, meaning the system won't fire up for heating or hot water.
Your boiler is failing to light because it cannot communicate with its internal control chip, usually occurring after a major circuit board repair.
Your boiler's internal computer chips are not communicating correctly or are mismatched, preventing the system from firing up.
Your boiler's main control board is struggling to communicate with its identity chip, often occurring after a recent repair or part replacement.
Your boiler has failed to recognise its internal configuration chip, often because a replacement circuit board was not set up correctly.
Your boiler is struggling to circulate water properly or the pressure is too low, causing it to shut down shortly after lighting.
Your boiler has detected that there is not enough water pressure or flow to operate safely, causing it to shut down shortly after lighting.
Your boiler has failed to ignite and cannot detect its own control chip, meaning it has shut down for safety.
Your boiler has lost all power and the control panel is completely blank, meaning the system cannot start or provide any heating.
BoilerFaultCodes