7 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 |
|---|---|---|
| 47-157-15 | Sargon 24 | 2008–2009 |
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Your boiler has automatically turned itself off because it has become too hot to operate safely.
Your boiler is struggling to accurately measure the temperature of your hot water, so it has stopped heating it to prevent the system from getting too hot.
Your boiler has lost the ability to accurately measure the temperature of the water flowing through its system, so it has shut down as a precaution to prevent overheating.
Your boiler has stopped working because it cannot light its internal flame or needs a simple drain clearance.
Your boiler has detected a fault with the sensor that monitors the temperature of the gases leaving your flue, meaning it has switched itself off for safety.
Your boiler has detected that the internal fan responsible for venting exhaust gases is not spinning at the required speed, so it has safely shut itself down to prevent unsafe operation.
Your boiler has detected that the internal exhaust fan is spinning when it should be turned off, which is preventing the system from safely starting up.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes