6 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
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 |
|---|---|---|
| 41-311-50 | 9/14 CBi RSF | 2001–2005 |
| 41-311-51 | 9/14 CBi RSF (LPG) | 2001–2005 |
| 41-311-52 | 14/19 CBi RSF | 2001–2005 |
| 41-311-53 | 14/19 CBi RSF (LPG) | 2001–2005 |
| 41-311-54 | 19/24 CBi RSF | 2001–2005 |
| 41-311-55 | 19/24 CBi RSF (LPG) | 2001–2005 |
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Your boiler has lost all power and is completely unresponsive, meaning it is currently unable to provide heating or hot water.
Your boiler is receiving a signal to turn on but is failing to start the ignition process, suggesting a communication or sensor delay.
Your boiler is failing to ignite or stay lit, meaning it cannot produce heat or hot water because the flame is not being detected.
Your boiler has stopped working for safety reasons and is locked out, meaning it needs a manual reset or a professional technician to investigate the internal fault.
Your boiler has stopped working for safety reasons and is waiting for you to manually reset it to try and clear the fault.
Your boiler has detected an unspecified internal problem and has shut down as a safety precaution.
BoilerFaultCodes