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By Andymart
Hello everyone,

It's my first ever post on here and I would just like some advice/help. I have had a few plumbers come and look at this issue but no success and I'm sick of trying different plumbers who just want to come and do the basics and the problem doesn't get resolved.

I have a large 4 bedroom detached house built in the year 2001, it has an Open Vented heating system with a new Worcester Greenstar 30Ri boiler. I have had all new radiators fitted in the house some vertical others normal panel radiators. I have also fitted new valves, a new heating pump, and a new Nest thermostat on the system.
The house has 18 radiators in the system, the other 15 are all working fine just these 3 vertical new radiators. They were changed to new after the power flush and were previously working fine apart from maybe 1

The issue I have is 3 of the vertical radiators on 1 side of the house 2 in the kitchen 1 in the second lounge are not getting very hot compared to the others. I can confirm they have no trapped air and water comes out of the top on each when I bleed them off.
When the plumber done the power flush it seams to of got worse not better?
I called the plumber back and he ran the system up to a high temp and then checked the radiators. He thought the kitchen radiator supply line was air locked, we drained off that radiator disconnected the valve and connected a hose which drained to a bucket and there wasn't much flow, very little in fact. The plumber then connected a foot pump and applied a small amount of pressure up the supply side and released it, more water did flow but not to what I would of expected to see. He then connected everything back up and put the supply valve back on but I'm still having the same issues? The flow with or without the supply valve was the same so the valve is not blocked and it’s quite new with all the other valves.

Do you think it maybe still air-locked on that supply side for the kitchen radiator and he hasn’t aloud enough time or pumped it enough? Is it worth disconnecting that radiator and again and checking the flow? And if it’s low flow then pumping air up the supply again using the foot pump and releasing the pressure until I get a good strong flow? Also will this radiator not having a full flow and return effect the other 2 radiators in the system which are suffering the same effect?

When we were pumping it up the supply side of the radiator we never exceeded 1.5 bar pressure as we didn’t want to cause any damage to the pipe work etc.

Any help/advice would greatly be appreciated as it’s really annoying me now.

Thank you.

User avatar
Hi & welcome to the forum.

turn all your radiators upstairs off. then turn all working radiators downstairs to 1-1&1/2 on the trv's
what happens to the non working vertical rads?
if nothing much then turn downstairs rads off apart from the one with no trv and the tower rads!
By SimonG
A lot of the vertical radiators have baffles inside and need to be fitted the right way round. They will have been identified with a flow inlet and it's important that the flow is connected to that. If not they behave a lot like the way you describe.

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Many thanks for your input and advice