central heating probs

All,
Basically, the downstairs radiators aren't working.
Central heating system: newly installed (three months ago) boiler (downstairs) and hot water cylinder (upstairs). System upgaded from pumped HW/gravity CH to fully pumped system. Pump in airing cupboard beside HW cylinder, one of those three way motorised valve thingies also in airing cupboard (which works).
Last week, before we switched the central heating on, I removed a rad in upstairs toilet to knock down wall (see other thread "Bathroom from scratch"). While removing the rad, I mde on of the valves leak, so had to drain the system and put an end stop on one of the pipes to the rad.
This was the first time I had drained a system, and I refilled it by untying the ball cock to header tank, then bleeding all the rads. As it was an emergency, 10pm at night, I did this without consulting the archives on here and bled bled the upstairs rads first, then downstairs, susbsequently finding out that this is the wrong way round. I haven't yet redained the system and refilled corectly.
On finding that downstairs rads weren't working, I did a few searches on here and tried the following:
- bled pump and checked that the impeller isn't stuck. No air came out of pump, and impeller spinning freely.
- switched off all radiators apart from one downstairs furthest away from pump/HWC, switched on heating...the rad which was previously stone cold warmed up within 1 minute...very hot to touch. Bingo I thought. Switched the rad off and did the same to all downstairs rads...switching of all rads apart from the one I'm working on...each heated up nicely. I also bled each one as it was switched on and hot water came out.
- when I switched on all the rads..again, only the upstairs ones warm up. This morning, every downstais one was stone cold, whereas before they were all slightly warm to touch, but not hot like the upstairs rads. The one in the downstairs bathroom is still stone cold.
I'm not sure what the problem is...each rad will heat up very hot if it's the only rad on...but switch them all on and the downstairs ones don't warm up. I'm pretty sure the pump is OK as a solitary switched on rad, no matter where in the house will heat up almost instantaneously.
Is this an airlock? It's just that I'm reluctant to call out the plumber/heating engineer that installed it as he's a really nice chap, and I don't want to look like a mug. Also, the rad ai removed will be going back on, after the weekend,and I don't want to have to call him out when I drain the system again and refit the rad. If I can't get it to I'll call him out after I've refitted the rad...but would like to at least have a warm shower room before...and it's not really in the spirit of uk.diy....
Another question...when bleeding the pump via the big brass screw on the back while the pump is on, is it normal to only have a little dribble coming out...I would have thought that it would spurt out...but would be happy to be wrong...
Many thanks for your help chaps...
Mark
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Did the system work when it was first installed ? The boiler is downstairs and the only pump is upstairs, along with the motorised valve ?
The only thing I can suggest you try, is to turn down all the valves on the return side of all the radiators. You'll have to find out how many turns the valves takes from fully open t completely closed, then set them at only half the amount of turns to give you roughly half closed on all of them. If you see what I mean.
But only do this on the return side of each radiator. And if it has only been installed for three months, then call the company back in and get them to sort it properly. If the system can't have a radiator removed / replaced when decorating without causing problems, then it ain't worth having. If it can't be drained and refilled for maintenance without it cocking up, then it is not doing its job properly. That's unless you've kinked a pipe somewhere, or forgetten to turn a valve back on that you've told us about. :-))
--
www.basecuritysystems.no-ip.com

Outgoing mail is certified Virus Free.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Assume that install is correct ? and problem is only since you removed a rad ?
If so, it could be as simple as an air-lock which can be a bugger to remove.
If pump is variable head - turn it up to maximum, then close off all rads at the lockshield valves, bar one ... which should be the furthest away from boiler. Crank up boiler temp to maximum, and set room stat to max .... hopefully this will blast the water into the rad past the air lock, keep bleeding the rad as you observe.
The extra temp in boiler will also help kettle off any air that gets into it, once you get one working add the others one by one.
If the rad still does not get hot - then work your hands along the flow from boiler - you may be able to see where it's getting to ... maybe as far as a non operating zone valve.
Some ideas for you anyway.
Once you get it working suggest you balance in properly - I wrote a sect on balancing for the FAQ many years ago, assume it is still there.
Rick
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thansk fro the advice chaps. Finally got round to fixing the heating, and this is is what I did:
Re-installed the rad I removed in the new position.
Drained the system.
When empty, I turned off all rad at normal valve and lockshield. Refilled system, and then filled each radiator in turn via normal valve (with blled screw out.
When each rad was full, switched on heating to full, and waited for system to warm up. Then carried out a balancing procedure to the best of my knowledge as I don't know the sequence of the rads.
This seemed to do the trick. All rads nice and hot, including all downstairs ones...
Thanks again...
Mark
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.