Central Heating Pump Overrun

[darkcloud154]

Hi All.

Just started having a problem with my central hetaing pump. Never used to do this before. Anyway, for some reason the pump is now pumping hot water of its own accord around the house without the central heating or hot water being switched on! The only way i can switch off the pump is by going into the garage and switching it off (there is an electrical swtich for the pump downstairs). When i switch it back on to start up the system, the pump starts up again!

The 3 way valve seems absolutely fine moving up and down like it always does. Does anyone have any thoughts as to why this is happening?

My system is a good 15-20 years old.

 

[whistler]

If this has happened in the last few days, it could be the internal frost protection in the boiler particulalry if the boiler is in the garage. I think most modern boilers have two stage protection, which initially just runs the pump to keep the water moving, but if it gets colder the second stage will fire up the boiler.

Edit: Just noticed your boiler is quite old, so maybe this is not the problem.

 

[D_Hailsham]

Which boiler do you have - make and model number?