Ever since moving into my house a year and a half ago, just two of my radiators don't appear to work. The whole system had been drained prior to my moving in so we re-filled the system and bled all the radiators. The boiler is on the first floor (in the bedroom believe it or not!). The two failing radiators are downstairs. One is in the bathroom, although the kitchen radiator that precedes it works fine. The other one that doesn't work is in the dining room, although the lounge radiator that is beyond it works fine. The pipes up to the valves get warm in both cases. If I try and bleed these radiators I get water straight away and no air. The valves appear to be standard manual valves from what I can tell - not thermostats and they have white cap over a lug that sticks up it that means anything to those who know. Is there something obvious I can try before getting the plumber in? All of the upstairs radiators and the one in the loft work fine. Cheers.