BoilerFaultCodesTechnical description
pump overrun
What causes this fault?
This is not a mechanical failure but a standard safety process where the boiler continues to move water through the system after the burner has turned off. It happens to dissipate excess heat from the internal heat exchanger, ensuring the components don't overheat or suffer from heat stress. If this code stays on for an unusually long time, it may suggest a bypass valve is blocked or the system is struggling to shed heat effectively.
DIY fix possible
Check that at least one radiator valve (usually a towel rail) is fully open to allow water to circulateMonitor the display to see if the status changes to a normal heating or standby mode after several minutesEnsure there is enough water pressure in the system (typically 1.0 to 1.5 bar)
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