i recently drained down my central heating as one of the pipes were dripping, i repaired the pipe but when i refilled the system the radiator was cold, there was water in the radiator as it was coming out the bleeding nipple, i took the rad off the wall and opened up both valves, the trv and lockshield, there was water coming out the lockshield side but not the trv side, i shut down all other radiators in house to see if this would help but it didn't, the pin in the trv is also ok, can anyone help, thanks ???