S.05 Low

Heatline S.05 Fault Code

Also written as S05 — same fault.

The Heatline S.05 fault code means: your boiler is not actually experiencing a fault; it is simply taking a short, normal break to run the pump and fan to dissipate excess heat after a cycle.. It appears on 8 Heatline models 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: Post run pump/fan
Typical repair cost £0 (including labour)

DIY fix possible

Wait approximately 5 to 10 minutes for the boiler to complete its cooling cycleMonitor the display to see if it changes back to a standard temperature reading or 'S.04'Ensure your room thermostat is calling for heat if the boiler does not restart after the wait period

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Heatline models that show the S.05 fault code

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

Source

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

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