Radiator stays cold after removal and refit

[MrQuorange]

Here is my story:
I have a combi boiler with 11 radiators.

Recently I removed one in bedroom 1 to redecorate, then refitted, bled and all worked OK.

In bedroom 2 I did the same, but having refitted and bled the radiator several times it refuses to get hot, and during bleeding, only water comes out - no air.

I have bled the radiator successfully with the heating off and both valves open. I closed off the input radiator valve and it bled fine. Then I opened the radiator valve and turned the TRV on the radiator output to the off position, and it also bled fine.

With both valve and TRV open, and all other radiators switched off, I turned on the heating. Both copper pipes either side of the radiator remained cold, so I started to bleed the radiator. After a while the input pipe warmed up, as did the top of the radiator and the water coming out of the drain plug. The output pipe and the bottom of the radiator remained cold, however. When I stopped the bleeding, the input pipe and radiator cooled down.

Obviously during all this I kept opening the valve on the combi to let more water in and keep the pressure around 1.5 bar.

The TRV appears to be working fine as the pin springs back out after being pushed in manually. The TRV has always been kept in the "fully on" position prior to the switching off and removal.

I have had 2 days of assorted attempts at fixing the problem and am now at the end of my tether. Please help!

 

[Armo74]

Possibly a balancing issue.

Have a look at FAQ's on balancing.

 

[gigz]

Take the valves back off and make sure there's good flow to both of them, might look like they're open but mightened be.

 

[jonwish]

As the above poster has mentioned. The easiest thing to do is probably take the rad off again and check that both valves are working + maybe flush the rad.

 

[MrQuorange]

Thanks for the prompt responses. I guess I will drain the radiator again and check both valves for flow as suggested. I'll need to be careful as a new carpet has been fitted, so I will be investing in a DrainEasy kit. Will let you know the outcome.

 

[mickthegas]

pin stuck on trv give it a whack with something

 

[MrQuorange]

Regarding the pin on the TRV, it is in the out position and when I manually push it in it springs back out. Is it possible there is something else sticking in the TRV which would warrant a few whacks?

 

[gigz]

Regarding the pin on the TRV, it is in the out position and when I manually push it in it springs back out. Is it possible there is something else sticking in the TRV which would warrant a few whacks?

Could be blocked, only way to prove it is disconnect and check.

 

[MrQuorange]

Yes the good old hammer came to the rescue; a few taps on the TRV fixed the problem. Sometime in the future I will need to replace the it but I think I've had enough for now.

Thanks for all your replies and suggestions, especially the "give it a few whacks"; all in the memory banks for the future.

And by the way, if anyone is interested, there's a brilliant product called DrainEasy which helps drain radiators without mess - Google it.

 

[Agile]

For next time look at "bucket test" in the FAQ on this site!