Low Information
S.15 on Glow-worm Ultracom sxi

Your boiler is currently cooling itself down after finishing a heating or hot water cycle, which is a normal operating state rather than a permanent failure.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

What causes this fault?

This occurs because the boiler needs to dissipate residual heat from the internal heat exchanger after it has finished heating your home or water. The pump and fan continue to run for a few minutes to ensure the unit cools down safely and prevents internal components from overheating. It is a protective measure rather than a breakdown.

DIY fix possible

Check that the radiator valves are open to allow heat to dissipateMonitor the display; this code should clear automatically after a few minutesNo action is required if the boiler returns to normal operation shortly after

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Related fault codes

S.05View →S.07View →S.08View →

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