Strange Behaviour From One Radiator?!

[Addy]

Hi,
I could really do with some help with a new radiator that I fitted a few weeks ago.

The system is a sealed system with a combi boiler and the pressure guage works fine. The radiator is now the first in the system.

When I first connected up the radiator and re filled the system, everything worked fine. A couple of weeks later we noticed that it was not heating up at all. All the other radiators in the house work fine. I have found that sometimes it will heat up and sometimes it wont. The first thing I tried was to bleed it, but the strange thing was that there would be a couple of drops of water then nothing, I even completely removed the bleed plug. I then cracked off the joints either side of the TRV and also the lock shield. There is absolutely no pressure either side of either valve assembly .

As I say, the system pressure gauge works (it drops when I vent any of the other radiators and comes back up when I re pressurise) and the system is set to approx. 1.1 Bar.

All the other radiators are fitted with TRVs except one small one in the bathroom. I have tried shutting all the other radiators off (closing the TRVs and the lock shield on the bathroom rad) and turning on the heating, thinking this could be a air lock and try to force it through, but this didn't work either.

My wife is at her wits end because it is now soooo cold

Sorry this is so long winded, but any help would be really apreciated.

Many thanks.

 

[seco services]

did you crack the joints before the trv/locksheild or after them ? trv to rad, locksheild to rad.

 

[Addy]

did you crack the joints before the trv/locksheild or after them ?

I cracked the joints on both sides of both valves. i.e. pipe / TRV joint and then the TRV / rad joint, then the same with the lockshield valve joints.

 

[seco services]

so your saying you could take the trv etc right off the pipe and no pressure/water would not release.

must be a blockage in the pipes.

 

[Addy]

Yep, that's correct. I could remove the TRV and lockshield from the pipes and the only water escaping would be from the radiator.

I have considered a blocked pipe, but why would it heat up sometimes and not at other times and also, surely both the supply and return pipes are pressurised and what would the odds be of intermittent blockages in both pipes at the same time be??

 

[seco services]

I have considered a blocked pipe, but why would it heat up sometimes and not at other times and also, surely both the supply and return pipes are pressurised and what would the odds be of intermittent blockages in both pipes at the same time be??

it is a strange situation but can't suggest any other reason.

did you install the pipework to the new rad ?

 

[Addy]

No, this is in a new single storey extension that we had built (structure and first fix).

There were the two 15mm plastic pipes loose by the main flow and return pipes and the other ends emerging from the wall under the window. The pipes run from one side of the room to the other in the ceiling void and then drop down in the wall.
So, I fitted the rad and connected it up, then fitted two push on 22>15mm tees to the feed and return circuit. Re filled the system and bled it etc. As I say, all worked great ........for a while

 

[Bahco]

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