BoilerFaultCodesYour boiler is simply cooling itself down by running the fan after you have finished using hot water.
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: DHW mode – fan overrun
What causes this fault?
This occurs when the boiler’s internal heat exchanger needs to shed excess heat after you have finished using a hot water tap. The boiler activates the fan to pull cool air through the unit to prevent internal components from getting too hot. It is a standard safety and maintenance process rather than a mechanical failure.
This may be more noticeable in summer when the incoming cold water mains temperature is higher, meaning the boiler has less naturally cold water to help it cool down quickly.
DIY fix possible
No action is required as this is a normal operating status and not a fault.Wait a few minutes for the fan to stop automatically.If the fan never stops, contact a Gas Safe engineer to check the control board.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like S.26 — no call-out fees, no surprises.
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