Stumped - hot pipes, cold rads

[Malc C]

Need some advice.

I've been having problems with my CH system, and whilst I can get some rads warm, its hard to balance due to a poor installation of some additional rads by a so called professional plumber. However, whats perplexing me is that the feed pipe to the rads downstairs is hot, but the rad is cold or at best luke warm, even on the point where the valve joins the rad.

I've tried bleeding the rads and all that comes out is clear water, no air. I've also closed and opened each valve (and lockshield where access is possible) and all move freely.

occasionally the Baxi Solo boiler will go into overheat, especially when just the CH is chosen. When CH is set and the boiler doesn't go into overheat, the system will run (ie the pump runs and the room stat is shown as calling for heat) but the boiler fails to cycle. If the CH and HW is engaged (often to the inital sound of water/air mix for the first few seconds) the boiler will cycle more often.

I'm currently waiting on two quotes for ripping out all the existing rds and pipe work and fitting new from the pump / boiler return, or possibly looking at doing this myself, however the thought of doing that in mid November is not appealing to 'er indoors so I'm looking for easy things I can do to try and nurse the system through the winter months.

Malc

 

[hi-spec plumbing heating]

is the f/e tank in loft filling the system with water.

 

[Malc C]

Hi,

Yes the feed / expansion tank has water - the ball cock is working fine and the water is cold. By that I mean its what you would expect to be for a tank in the airing cupboard, (we have no loft) ie it not stone cold as if it was constantly or freshly drawn from the mains.

I've just tried an experiment, and opened one of the lockshield valves fully and the rad got hot, but shutting this down didn't make the rads in the living room heat up like it should.

The system also takes for ever to get warm except the bathroom rad which is about 8' run from the pump, and this is one of two rads that have the lockshiled valve in an un-accessable place ( like behind the bath pannel !) - so I have to balance this one by shutting down the feed valve, which I think is causing part of the problem as this builds up pressure which can be heard releasing when the HW is engauged and the 3 way valve opens !