How to bleed a radiator with no bleed valve?

[Helveticus]

The radiators in our flat are warm only at the bottom and there is a trickling sound when the CH is on, so they almost certainly need to be bled. There is a snag, however: on one end they have one connection to the heating system via a Danfoss thermostatic radiator valve (TRV) at the top and a second connection to the heating system at the bottom and that's it: the other end has only screwed-in stoppers top and bottom with *no* bleed valves. Do I have to (partially) dismantle the TRV to bleed the rad? Our flat is in the middle floor of a 3 storey house in Switzerland with a communal CH system. Could it be that bleed valves are only installed in the top floor flat?

[gasman0007]

undo one of the stoppers sloely it will bleed through the thread

[Helveticus]

Hi gasman0007, Thanks for your answer. I have a sneaking suspicion that there must be some other (easier?) way to do it, since the screwed-in stoppers have been painted over and clearly have not been touched for ages.

[mrpeter]

Some radiators have the bleed screw at the back of the rad at the top.

[AlBags]

Slacken the TRV connection to the radiator off to let out air. If you slacken the blank, you may damage a seal.