View Full Version : pump help

14-01-2008, 07:56 PM
my pump runs for about 1 hour after the timer turns itself off is this normal?

02-02-2008, 02:10 AM

I assume you are talking about your Central Heating Pump, is this correct?

Your pump should continue to run for a short while after the timer turns off, this allows for the system to cool down slightly, especially the heat exchanger in the boiler, to stop what is known as "Kettling" or boiling of the water at the hottest part (Usually the boiler), which would introduce air etc in to the system and could vapour lock the whole system, or even worse crack the heat exchanger.

If your pump continues for this long, then it would seem that either 1 of the thermistors in the system is faulty or you might have the heat (Temperature setting)turned up too high either in your hot water cylinder or on your boiler. According to some plumbers you should not have the system set above 60 Deg C and others say 70 Deg C, but I have known people turn the temp setting up to 90 on their hot water cylinder.

I hope this helps.

02-02-2008, 08:04 AM
Seems like you may have a fault with the pump overheating and the thermo cutting in, which would cut the pump off, and when it cools down, it would allow the pump to re-start,