S.05 Low

British Gas S.05 Fault Code

Also written as S05 — same fault.

The British Gas S.05 fault code means: your boiler is briefly keeping the internal parts running to cool itself down after heating your home or water.. It appears on 1 British Gas model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: pump / fan overrun
Typical repair cost £0 (including labour)

DIY fix possible

Wait for 5 to 10 minutes to see if the code disappears naturallyEnsure your radiator valves are open to allow heat to dissipateCheck if your thermostat is still calling for heat

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British Gas models that show the S.05 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

British Gas S.05 fault code information on this page is sourced and cross-checked against the official British Gas service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026