Downstairs radiators cold

17 Oct 2016
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United Kingdom
Please can anybody help me!

I've had a new worcester bosch combi 28cdi fitted, new radiators downstairs (one of which used to get hot but doesn't now). Honeywell thermostat, magnaclean.

Downstairs radiators are stone cold - not even hot pipes to the rads.
No air in the radiators - all bled.
Checked TRV's - they are not sticking, lockshields are open.
Top radiators all work absolutely fine.
All have been bled and not much air in any of them.
The boiler is not loosing any pressure and is at 1.5 bar.
Have locked off all the top radiators to try and push water through the downstairs - nothing.
Did a complete drain down and refill (with inhibitor) - still the same problem.

The pump must be running OK to push up to the upstairs radiators?

I'm trying to get the plumber back but he says it might not be til next Monday. Is there anything I'm missing that I can do in the meantime? Thank you so much to anyone out there that can advise!
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Some suggestions.

1) Are they on separate zones with separate upstairs / downstairs control?

2) I came across an installation at a girlfriend's house (Now Mrs Stem :) but I digress) where the pump had failed, all downstairs radiators were cold, but the upstairs radiators were getting hot by natural circulation.

3) I was going to suggest turning off all those that are heating up, but I see you have already tried that!
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I don't think they are on zones. 3 of the 4 radiators are direct replacements on existing pipes. The one replaced in March worked fine and the other old ones worked too. Now there is one new addition and I've replaced all downstairs rads for new they don't seem to work.
Did the installer not test & commission on completion?
I smell a rat.
I found the rat..... they hadn't turned the valves on to the magna clean!! so now working thank you very much for trying to help and replying much appreciated
Odd that the upstairs radiators were still working with the Magnaclean valves closed.

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