This radiator was working fine for two years. It stopped working about a year ago. The rad had been moved from one part of the room to another three or four years as go.This was done by professional plumbers by extending piping from the next room. The rad looks like it id the last on the circuit, and physically the closest to the boiler. CHECKLIST OF THINGS DONE SEPARATELY ON DIFFERENT OCASSIONS BUT NO LUCK IN GETTING IT TO HEAT UP Bled radiator a few times. One time the inflow pipe and part of the rad warmed up just barely (not warm but you can feel there was a bit of barely warm water in there). We had central heating on an hour earlier. TRV pin is fine moves down then up freely if pushed down TRV open Lockshield open Closed all upstairs rads but kept downstairs open hoping to increase flow to the downstairs rad including the non-working Closed all but one other radiator hoping to concentrate flow into the non-working rad Drained the system once or twice over the last few months again no luck One time the TRV pin leaked after playing around with the pin. Considerable amount of water flowed out into a bowl placed just under under the TRV. This water along with the inflow pipe and the TRV was boiling hot. I though I had finally fond it but the rad did not heat up at all and the return pipe along with lockshield valve stone cold as always. Why didn't this very hot water get into the rad? Could the valve be faulty, or is there a block on the return pipe leading up to this radiator. I can pinpoint exactly where the pipes normally go cold when the heating is on. Its at the point where this room's pipework meets the pipework to the room next door, where it is connected from.