advice needed

[commonroad]

hello all
Got a slight problem I could do with some advice about.
Recently moved into a house with an ageing boiler (Potterton Profile Prima 40e) had the local gas fitter come round and give it a service, and advise us as to how much it would cost to replace etc.
We decided to leave it until next summer as he said it was working fine at the moment, so leave for the time being. Best to get settled in etc etc.

We added a few radiators during the summer, mainly upstairs. Also replaced the central heating pump while we were on with that. So the boiler is now supplying 7 radiators.

The problem we have is that while the central heating works fine, the 2 radiators we need to warm up (living room and dining room) dont seem to want to warm up. the hot water gets so far, then gives up. The radiators upstairs warm up fine. All the radiators have been bled and have been balanced

has anyone got any thoughts idea's about what could be the problem?
Thanks in advance

 

[Boilerman2]

The Radaitors have NOT been balanced- otherwise they would all be working!!

what happens when you turn off the upstairs rads do the problem ones then heat up?

If not it would be worth pulling some water through the flow and return pipes, to remove any air locks in the pipe work, I assume that any TRV's fitted to the problem rads have been checked to ensure that the pins are not stuck down??

 

[commonroad]

hello
when I turned off all of the radiators upstairs, the downstairs radiators didnt heat up at all.
The new radiator in the dining room has got new valves, I replaced the old valves in the living room over the weekend.
Just wondering now if the boiler and/or the pump is not strong enough to supply the radiators.

 

[Boilerman2]

If you are saying that NONE of the downstaris rads are heating it may well be down to the pump, have you vented the pump after re-filling??

 

[commonroad]

Hmmm, not sure.
we replaced the grundfos pump. re-filled the system, bled it and away we went.
How do you vent the pump?
Is that something i can do, or do I need to get the plumber around?

 

[Boilerman2]

So! you have changed Rads, the pump some valves??
sounds like you have swum out of your depth I'd give your heating engineer a call!