I've got a double rad with a TRV at one end and a lock shield valve at the other other. The rad was stone cold but the pipes one either side were warm. A heating engineer closed the TRV and lock shield valve, then undid the nut connecting the TRV to the rad (I think he took off the lock shield valve as well but I'm not sure) and drained some of the water. Not all the water, about 2 litres I think. Connected it all up and the rad is working fine now, not piping hot everywhere but well enough to keep the room warm.
What has he done and is it a permanent fix?
What has he done and is it a permanent fix?