S.04 Low

British Gas S.04 Fault Code

Also written as S04 — same fault.

The British Gas S.04 fault code means: your boiler is working exactly as it should and is currently heating your radiators.. 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: burner on. NORMAL OPERATING STATE FOR CENTRAL HEATING
Typical repair cost £0 (including labour)

DIY fix possible

No action requiredMonitor your thermostat to ensure the house reaches your desired temperature

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British Gas models that show the S.04 fault code

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

Source

British Gas S.04 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