Pump problems

[Overflow]

I moved into my house in the summer and turned on the heating recently. The 2 downstairs rads next to the gas fire barely warm-up at all. The upstairs rads are hot apart from the bottom couple of inches which are cold. Hot water is fine. Doing my homework, suggests a pump problem. But where do I find this pump to check it out?

System is open, I think it\\\'s a back boiler. Also upstairs rads get hot when HW only is selected.

Any help - esp on the pump v. welcome.

 

[dazhaz]

First things first, have you bled the radiators?

 

[corgiman]

SOunds scarily like sludge build up with "two inches at bottom of rads" but dont think this is the reason

Does the system have a three port vale if so that might be the problem there are loads of posts of them mate so have a look

 

[Overflow]

I've bled all the rads but found no air, cheers for the advice on 3-port valves I'll go and do some reading. From the other post about cold downstairs rads, the pump still sounds interesting, I'll keep looking.

Cheers