16 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Heatline Capriz
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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 |
|---|---|---|
| 47-157-16 | Sargon 30 | 2008–2009 |
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 lost its connection to an optional outdoor temperature sensor, but this is usually just an informational message and your heating should still work normally.
Your boiler has detected that the water pressure inside the system is outside of the safe operating range, so it has shut down to prevent damage.
Your boiler has automatically shut down for safety because it detected that the internal water temperature has become dangerously high.
Your boiler has failed to light the flame needed to produce heat or hot water, meaning it has safely shut itself down as a precaution.
Your boiler is struggling to accurately measure the temperature of your hot water supply, so it has stopped heating water to prevent overheating.
Your boiler is failing to light the fuel inside to start the heating process, so it has shut down as a safety precaution.
Your boiler has stopped working because it is unable to accurately measure the temperature of the water inside the system.
Your boiler is struggling to detect if the internal fan is spinning correctly, which causes it to shut down for your safety to prevent the build-up of harmful exhaust gases.
Your boiler has failed to start because it cannot detect a flame or drain water properly, so it has safely shut itself down to prevent any issues.
Your boiler has detected an issue with the flame ignition process and has safely locked itself out to prevent fuel waste or unsafe operation.
Your boiler has detected a fault with a safety sensor that monitors the temperature of the gases leaving your flue, meaning the boiler has shut down to prevent overheating.
Your boiler is struggling to detect the outside temperature, so it is defaulting to a standard operation mode to ensure you still have heating and hot water.
Your boiler is struggling to read its own temperature because a sensor responsible for monitoring the heating water has likely failed or sent an incorrect signal.
Your boiler has detected that the air circulation system is not operating at the correct 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 a safety fault that prevents the boiler from starting up.
Your boiler is working normally and is simply indicating that an outdoor temperature sensor is active and helping to adjust your heating efficiency.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes