Please help! 1 cold radiator

[SGraham99]

View attachment 368174

Top and left side of the rad now hot but nothing at the bottom. Similar to the rad on the other side of the wall

 

[CountryFan]

Top and left side of the rad now hot but nothing at the bottom. Similar to the rad on the other side of the wall

Can you post one with the lockshield cap removed? Also, try removing the trv head, see if any improvement.

 

[SGraham99]

Can you post one with the lockshield cap removed? Also, try removing the trv head, see if any improvement.

Swapped the trv head with one from a rad that was working

 

[JohnD]

half an hour after starting the heating from cold

 

[SGraham99]

Will try again tomorrow from cold. Is there a reason it has to be half an hour from cold? Thanks

 

[JohnD]

So you know you're starting from cold. Give it time to stabilise, cold or hot.

Don't keep checking or changing anything more frequently

 

[cross thread]

The thermostat valve body pin maybe free but the valve can stick,can you remove to check?

 

[JohnD]

Turned a very hot radiator off and now the pipe feeding the cold rad is too hot to hold but actual rad is barely warm.

Flow is entering the radiator, so the TRV is not jammed shut.

 

[cross thread]

It may be partially open JohnD but not enough for a decent flow

 

[SGraham99]

Close both valves on the problem rad. If system is sealed / pressurised ensure pressure is 1.5 bar . Then open its bleed valve ,have a towel to hand ,let water run out until it stops running. Open the TRV and see if water starts ,and continues , to flow out . If it doesn't the TRV is faulty or the pipework to it is blocked.
If water does flow out well,close the TRV and open the lockshield and repeat the test to see if water flows.

Tried this today, water was flowing out when both valves were open

 

[SGraham99]

Both radiators furthest away now aren’t getting hot at all and the pipes feeding them are barely warm, might be time to get a professional in…