BoilerFaultCodesWhat the manual says
Manufacturer manualpump overrun
What causes this fault?
This occurs when the boiler has finished heating your water or radiators and needs to dissipate the remaining heat from the internal heat exchanger. The system keeps the pump running for a few minutes to circulate water and cool the components down to a safe temperature. It is a standard safety feature of the design rather than a sign of a broken part.
This code may appear more frequently in winter when the boiler is working harder to heat your home, leading to higher internal temperatures that require longer cooling periods.
DIY fix possible
Wait for the code to disappear naturally as the boiler cools downEnsure at least one radiator with a manual valve is fully open to allow water flowCheck that the system water pressure is between 1.0 and 1.5 bar
Avoid the next call-out bill
A cover plan would handle faults like S.27: no call-out fees, no surprise bills.
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