BoilerFaultCodesWhat the manual says
Manufacturer manualpump overrun
From this model's manual
Verified against the Glow Worm Flexicom Cx installation & service manual, page 45.
What causes this fault?
This is a normal function of the boiler rather than a mechanical failure. It occurs when the burner stops firing and the internal pump continues to circulate water to dissipate residual heat from the heat exchanger. This prevents the internal components from overheating and helps extend the lifespan of the appliance.
DIY fix possible
Wait for the code to disappear naturally as it is a normal part of the boiler's operationEnsure at least one radiator with a manual valve is left fully open to maintain water flowCheck that your system pressure is between 1.0 and 1.5 bar on the display
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