I thought of this so I put the trv on another rad and it worked fine.If I take the head off the rad it still stays cold until I bleed off some water from the lockshield.Could it be the return pipe is furred up causing the problem.
Just had a single radiator with no trv replaced for a new double convector rad with trv by a heating engineer problem is it wont run with the trv.I know the trv is fine but if I leave the head on it just goes cold.
I have to remove head shut off valve with the decorating cap and then draw water...