During a recent decorating phase I had one of the downstairs radiators off the wall for a few weeks. I have now re fitted the radiator but can get it to warm up and the pipes are cold when the heatings on. I have bled the radiator so that's not the problem. It has a honeywell TRV fitted and the pin seems to move up and down but when i turn the other ground floor raditators off the pipe to the one in question warms up but the radiator remains cold. any ideas?? is the TRV knackered??