BoilerFaultCodesWhat the manual says
Manufacturer manualpump overrun
From this model's manual
Verified against the Glow Worm Ultracom 2 Cxi installation & service manual, page 52.
What causes this fault?
This occurs when the boiler has finished heating and needs to dissipate residual heat from the internal heat exchanger. The pump continues to circulate water to prevent the internal temperature from rising too high after the burner has turned off. It is a normal safety function designed to protect the boiler's components from thermal stress.
DIY fix possible
Wait for several minutes as this is a normal part of the boiler's cooling processEnsure at least one radiator with a manual valve is fully open to allow water flowCheck if the boiler eventually moves to a different status code like S.0 or S.30
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