1 Rad Not Working

[Danv44444]

Hi Guys, Im having a problem with 1 radiator that wont work properly. The rest of the system heats up fine apart from one on a dropper downstairs. I Turned all the other radiators off and left just the one on and it got hot at one the lockshield end and not at the trv end so i assumed it was a faulty TRV. I changed the trv and the problem is still happening? Im wondering what else it can be thats stopping the rad from warming. I Have tried balancing the system and it just wont heat up. Am i right in sthinking somthing must be restricting the pipework somewhere and the water is just taking the easiest route and missing the rad out? Neither side of the rad gets warm at all.
Im Starting to think a power flush might be requierd? or maybe try changing the lockshield too?

Any other ideas?

 

[JCplumb]

Had a very similar scenario last week.
Moved all the furniture and lifted carpets to find the run for the rad, it went up from boiler then split into two runs, 1st run very short 15mm to an 'always on' bathroom rad and one bedroom rad, 2nd run was done in 10mm and dropped to 1 downstairs rad, then 1 bedroom rad, then went all round the house still in 10mm then was adapted to 15mm to drop down to the living room rad - this was the rad that wasn't heating up. Not surprising really as there was just no incentive for the water to get there.
I repiped the living room rad joining the 15mm run to the original 15mm drop, it still didn't heat up due to airlocks at the top of the drop, I tried leaving it as the only radiator on and only got heat to the lockshield side of the rad, so snatched the Speedfit joints at the top of the drop until the air was gone and voila - all sorted.

 

[SimonG]

Did you take the rad off and run water through trv and lock shield? Might be an air lock.

Wgat size pipe?, is it sealed system?

 

[Danv44444]

Its Open vented on 10mm droppers. I didnt take the radiator off and try getting water through the trv and lockshield. Maybe its worth a go?

 

[SimonG]

I would of, gives you an indication of flow through the valves.

 

[Danv44444]

Do you think if there's not much flow you,d powerflush?

 

[SimonG]

I don't powerflush, but it's not part of my business. It will give you an indication of any issues though.

I extended a sealed system into a garage conversion, an extra three rads. I screwed up the filling of the new bit. I normally leave the valves closed at each end and then up the pressure and fill the rad first from one end and then the other to pull out all the air in the pipes. This time i just left the valves open. I had to remove the vent tapping and put a flexi hose (they do have some uses) onto it and ran both sides into a bucket until I'd got rid of all the air in the pipes. Totally my fault and cost me an extra half hour filling up. But even shutting down the other rads on the system wouldn't shift the air lock.

 

[bewsh]

You've either got an air lock or a restriction/blockage.

www[dot]youtube.com/watch?v=bAeRurEExBs
this guy gives a pretty good demo of an easy way to remove air locks without taking the radiator off the wall.

But if you want to take the radiator off, it might be a good plan to take it out the back, get a hose and force water through it to get rid of any sludge sitting at the bottom of the radiator.

 

[Danv44444]

I went back today. Took the rad off. Ran a hose through it, put a hose on the lockshield side and ran water through and then did the same on the trv side.

the rads now working fine. Thanks guys