We had a new radiator fitted in the conservatory yesterday. It has been run from pipes that were in existence in the kitchen where a radiator was removed. The new rad will not get hot. We have bled the system and the pump. If we open the bleed valve on the new rad and let loads of water run out whilst running round opening the bleed valves on all the upstairs rads the hot water gets to the new rad but only heats up a couple of inches. We have turned the TRV off and bled, water comes out, we have turned the valve off the other end and opened the trv and bled, water comes out. I phoned the plumber who told me we need to wait at least 2 weeks for the system to "settle" before the rad will work. Is this right???