TRV RT212 Problem

[stevedonovan]

I have just taken on a house with RT212 TVR's fitted. They all work except one.
I have tried bleeding the rad but it is still cold.
I have tried removing the TRV top in order to try and release the pin. However, the pin seems to be raised (out) and with pliers I cannot move the pin in or out.
I checked with another TRV valve that is working and that seemed the same i.e I could not move it in or out.
Thus replacing the TRV does not seem to be the solution as both non-working and working valves seem to be in the same state.
Have you any ideas as I am now at a loss on what to do?
Thanks for your help.
Steve

 

[stevetheplumber]

get a shifting spanner about 12 inches long hold the head and use the handle to tap hard on the valve body avoiding the threads for the head ,with luck the jumper will lift best done with the heating on as youll feel the heat come through