BoilerFaultCodesYour boiler is briefly running the pump after the heating has switched off to cool the system down, but it is taking longer than expected to move the residual heat away.
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: Heating mode – pump overrun error
What causes this fault?
This issue occurs when heat is trapped inside the boiler's heat exchanger after the heating has turned off, usually because the water isn't moving away quickly enough. The most common reasons are a pump that is beginning to fail, trapped air in the unit, or a build-up of sludge in the system pipes that is restricting flow.
This fault often appears at the start of autumn when the heating is turned back on after a long summer break, as pumps can seize or struggle after being idle for several months.
DIY fix possible
Check that all radiator valves (TRVs) are fully open to allow water to circulateEnsure the system pressure is between 1.0 and 1.5 bar on the front displayClear any air from the system by bleeding your radiators
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