DIY Doctor UK DIY Forums

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 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 seems 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 reconnected 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 connected 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.

Andy

Hi andymart
Turn all radiators off then with the heating on open each of the problem ones in turn - they should get hot. If not check your pump is on max and try again if it wasn’t.
Regards S

Hi Stoneyboy,

I have done what you mentioned previously, I ran the system on Max temp with the 3 problem radiators and they all eventually got warm. The problem is they are taking over 1 hour or so to get just warm. When I open up to the rest of the house radiators they seem to struggle even more. I think I must have some issue inside the pipe work either a small blockage/restriction or maybe it gets air locked?
It’s really annoying as I ha e tried to make the system efficient with new rads and valves etc and now all i have is problems!

Hi andymart
Did you run just one radiator at a time?
If you can trace the radiator manufacturer check whether they have a flow bias ie flow connection can Beto one side only.
Regards S

I have previously done 1 at a time and they do all get warm. This time I did the 3 together and although it took over 1 hour they did get warm eventually. But when all the system is on these take forever to get any temperature and 1 in particular doesn’t even get warm.
The radiators are Milano Aruba, vertical radiators from Bestheating website, they are 1780mm x 472mm double panel with Milano minimalist chrome valves.

Hi andymart
Are the feed and flow connections at the bottom of the radiators? If yes were baffled fitted as recommended by the manufacturer?
Regards S

The feed and flow connections are at the bottom of the radiators on opposite sides on all the vertical ones. The baffle you mention? Nothing in the manuals was mentioned about a baffle and the fitting/installation manual either. I unpacked all the radiators and checked them all and the valves when they were delivered to make sure everything was okay before the plumber came to install.
There was no extra parts or baffles in any of the 5 radiators?

Hi andymart
The Milano fitting instructions on their web site for the Aruba recommends fitting baffles where the two bottom connections are used. Perhaps they are an optional extra - no baffles are needed when one top and one bottom connection are used.[attachment=0]EBB735F5-4F38-4226-A89B-AC8995CAFF77.jpeg[/attachment]
Regards S