12 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 |
|---|---|---|
| 47-291-03 | Combi Compact HRE 36/30 | 2008–present |
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Your boiler has detected a problem with its primary temperature sensor and has stopped working as a safety precaution.
Your boiler has detected a faulty temperature sensor, which is preventing it from correctly reading the heat levels and stopping it from working properly.
Your boiler has detected a problem with its primary temperature sensor and has stopped working as a safety precaution.
Your boiler has detected a problem with its primary temperature sensor and has stopped working as a safety precaution.
Your boiler has detected a problem with its primary temperature sensor and has stopped working as a safety precaution.
Your boiler has detected a problem with the temperature sensor that monitors the water returning to the unit, causing it to stop running for safety.
Your boiler has detected a problem with the temperature sensor that monitors the water returning to the unit, causing it to stop running for safety.
Your boiler has detected an inaccurate reading from an internal temperature sensor, causing it to stop operating to ensure your safety.
Your boiler has detected a problem with the temperature sensor that monitors the water returning to the unit, causing it to stop running for safety.
Your boiler has sensed that the water returning from your radiators is hotter than the water leaving the boiler, which usually means there is a circulation problem or a sensor fault.
Your boiler has detected an internal fault with the component that controls the gas supply, meaning it has shut down to keep your home safe.
Your boiler has detected an internal electrical fault with the component that controls the gas supply, meaning it has safely shut itself down to prevent operation.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes