Central heating pump problem

[montrano]

Hi guys,

I have a problem which I believe to be the pump, but I thought I'd ask people with more experience before I go and replace it.
The radiators downstairs are cold and upstairs hot.
I had a guy in doing a service on the baxi back boiler and he said the pump was fine, that it was probably sludge and wanted £450 to fix it.
I had a look at the pump and its starting to spin up, then cuts out. The flashing lights give an error code in the manual which just says unstable operation.
I noticed while the boilers running, theres bubbling in the hot water tank.

What else can I check to diagnose or fix it. The back boilers was just serviced and is working fine.

 

[Mike2007]

Change the pump, it's easily done.

 

[Ihavenojob]

Assuming you have a conventional (heat only) boiler with 2 tanks in the loft, try and find where the cold feed enters the system & see if a magnet will be attracted to it, it could be a blockage there which could lead to no heat downstairs. A blockage there would also cause water to be pumped over via the open vent pipe into the smaller of the 2 tanks (expansion tank). Just noticed the "back boiler" bit, so it is heat only.