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Rick Ridley
Rick Ridley, UK Heating Engineer
Category: UK Plumbing
Satisfied Customers: 1561
Experience:  30 Years on the tools, now retired, Ex CORGI
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My problem is the upstairs rads are all cold while

Customer Question

Hi Andrew, my problem is the upstairs rads are all cold while downstairs rads are working fine. Just had 2 replacement towel warmers installed so system was partially drained through the drain on the boiler with all upstairs rads isolated and then system refilled. Pump seems to be working ok but just cant get any heat to upstairs. All rads have been bled so no air is present.The header tank has water in it so the system seems to be full. The feed pipe to upstairs tees off from the downstairs feed next to boiler but it does not get hot, so maybe an air lock? Pump is an old SMC commodor 130 (70w) on the return side but I'm not sure how to bleed it as it does not have a central bleed screw like other models.The boiler is an old Glow Worm 65-80.If you have any suggestions as to likely cause I would be grateful.
Submitted: 2 years ago.
Category: UK Plumbing
Expert:  Andrew Smith replied 2 years ago.

Sounds like an airlock then preventing circulation, I would suggest you keep trying one single upstairs radiator at a time until you get a gurgle and it shifts.

Customer: replied 2 years ago.
when you say keep trying, do you mean run the system with only one upstairs rad turned on at a time, or keep bleeding one upstairs rad at a time.
Expert:  Andrew Smith replied 2 years ago.

Forget bleeding.

Just keep running until the air is shifted and is in a radiator, then bleed at the end.

Customer: replied 2 years ago.
OK thanks, ***** ***** does not resolve it what other actions can be taken?
Expert:  Andrew Smith replied 2 years ago.

Try removing the screw from the pump and leaving it out with a tub under

Customer: replied 2 years ago.
As I mentioned there is only a screw on each side no central could they be for bleeding? Picture attached.
Expert:  Andrew Smith replied 2 years ago.

Ok, borrowed from Noah's boat it's that old!

It's hard this as you have nowhere to vent then.

I can only suggest to keep doing what you are doing, unless you fancy pushing water up the drain point with a hose pipe to stir things up?

Customer: replied 2 years ago.
Best take it to the antiques roadshow then.
I was considering a back flush from the mains - I presume the only danger is the water in the system over filling the header tank?
Expert:  Andrew Smith replied 2 years ago.

Perhaps half empty the system again and then when you refill go and vent the further first.

As long as you do not back fill too quickly then the overflow on the tank should cope.

Customer: replied 2 years ago.
Thanks Andrew, not had any luck with shifting the air lock yet so will try a back flush tomorrow.
So if I understand you correctly I should bleed the rad furthest from the boiler first after back filling from the mains. Yes?
Expert:  Andrew Smith replied 2 years ago.

yes, that will shift the most air in one go