Central Heating....in half the house!

[mercyme]

My central heating is only working upstairs....radiators are hot as usual, downstairs stone cold, and it's freezing! Does anyone have a clue as to what might be causing the problem please?

[nabob]

This happened to my parents and it was the pump that had to be replaced.

[mercyme]

Theres a downstairs pump as well as an upstairs pump? D'oh! really? Well the things you learn!

[craft1948]

I am the least practical person on here but........I had this problem in my last house (I now live in a bungalow) but the BF bled the pump and this worked. I only had one pump?

[mercyme]

I thought we just had the one pump in the airing cupboard upstairs, but I'm happy to be proved wrong, sounds like I need a plumber then?

[honky-tonk]

Never heard of 2 pumps, we only have one and thats in the airing cupboard.

[vulcan]

Mercyme, In my system the radiators upstairs are heated by conduction,it's the ones downstairs requires the pump. If you have a piece of wood handy put one end to the pump and the other to your ear, you should be able to hear it working[or not]

[mercyme]

There's always a lot of noise when the heating is first switched on as though the pump is running, but then maybe thats just noise from the boiler and water tank, it's definitely not that the radiators need bleeding then? the system is approx 21 years old btw.

[buildersmate]

Vulcan speaks with sense here - it is most unlikely that your system has 2 pumps, though there are exceptions (my system has 3, but that's just being flash). As he (nearly) says, convection (not conduction) is driving some hot water around the system upstairs only. It happens because hot water is less dense than cold water so rises.
I am 95% certain that your pump has failed.
Holding your ear against a pump that is (purportedly) running and listening for vibration is not a good test - mainly pumps fail to rotate the impeller though electricity connected through the motor mechanism still makes it vibrate, even when it is doing nothing.
A fear its a plumber job unless you fancy getting your hands dirty. Make sure he fits a decent pump (Grundfos). Should be an easy job if there are lockshield valves on each side of the pump connections. New pumps cost about £60.

[mercyme]

Thanks for all your answers, we did buy a new pump, it's still in it's box so looks like I'll be finding a plumber to fit it....thank you all once again.