I have a pressurised system and I removed a radiator which never seemed to get warm. I assumed that it was probably full of gunk. My wife wanted the radiator on a different wall so I removed the old pipes and moved them to the new position. I also bought a new radiator but cant get it to warm up. I flushed the pipes through before fitting new valves and then attaching to the radiator. All other radiators are fine. So far I have tried:- 1. Turning all other radiator off to force the flow to the new radiator 2. Draining new rad down and ensuring that there is sufficient flow through the pipes to the new rad. 3. Removing TRV and replacing with a traditional value. 4. Pressuring system to 2Bar When I open the valves (after refitting) water flows to the radiator and it warms up then slowly goes cold. Any other suggestions please.