BoilerFaultCodesTechnical description
pump overrun
What causes this fault?
This occurs when the boiler needs to move residual heat away from the internal heat exchanger after the burner has switched off. It is a standard safety function designed to protect the internal components from overheating and to prevent the water from boiling inside the pipes. If this remains on the screen for an unusually long time, it may indicate that water is not flowing freely through your system bypass.
DIY fix possible
Check that at least one radiator (typically the one in the hallway with no thermostat) is turned fully on.Ensure your magnetic system filter, if fitted, is not blocked.Wait up to 10 minutes to see if the code clears automatically as the system cools down.
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