BoilerFaultCodesTechnical description
pump overrun
What causes this fault?
This occurs when the boiler detects that the internal temperature is remaining too high after the burners have switched off, prompting the pump to stay running to move heat away. The most common reason is a restriction in water flow or a pump that is beginning to struggle, meaning the system cannot shed heat as quickly as it should. Occasionally, it can be caused by a sensor incorrectly reporting that the heat exchanger is still hot.
This is more common in summer when radiators are turned off, as the boiler has fewer paths to dissipate heat after providing hot water.
DIY fix possible
Check that all radiator valves are open to ensure good circulationMonitor the display to see if the code clears once the cooling cycle is completeEnsure there is no air trapped in the system by bleeding radiators