Hi I have just bled the radiators in my house as two of them have been bubbling and doing the warm at the bottom cold at the top thing for a few days. All the radiators are working fine except for the one in the dining kitchen which is stone cold. I'm not sure if it is the first or last one in the cycle as it was newly fitted 3 years ago (we have had no problems till now). It has 2 panels. There are two pipes - one going in and one going out and they come down from the ceiling. At the ceiling, the incoming pipe is hot, the outgoing pipe cold. Then the pipes are boxed in (this was only done a couple of weeks ago) and at the bottom, both pipes are stone cold. Is it possible that there is air in the pipe preventing the hot water from coming down? Should I bleed the radiator for longer? I have bled both panels until water comes out. Or is it possible to bleed the valve? Any help gratefully received!!