Vertical Radiator Not Heating

Hi Everyone,

First post, but I have read around my issue and not managed to come up with a fix. I bought a lovely second hand vertical radiator - There was no rust on it, it was in good condition and is relatively modern. I had it fitted by a plumber but it simply wouldnt heat up propery. When the heating is on, it gets no heat going through the bars. I can feel the heat going across the bottom between the valves, but nothing up the bars. Reading around this, I have tried switching off all other radiators in the house to force all flow through it, the plumber als reversed the flow and tried a few things too but to no avail. The only thing that gets heat up some of the bars to about a thrid of the way is when I bleed the radiator repeatedly. However this is short lived and when I sotp bleeding (filling a bucket with the drain off a number of times) the heat begins to disappear. I'm finding that the heat will flow up one bar to the top and this heats the top horizontal peice (which becomes very hot), but all other bars still only remain warm to a thrd of the way up. I have bled it until the hot water comes out and continued until the top bar is very hot, but nothin in the other vertical bars.

Can anyone offer up any advice - I would normally give up, but I spent quite a bit of time stripping the external paint and repainting it to match the room.

Thanks,

Lee