2 Cold Radiators

[Grego]

I removed a small radiator to tile in the upstairs bathroom and when I put the radiator back it remained cold, at the same time the radiator on the landing stopped working (this had not been removed at anytime).

When I tried to bleed the radiators, water comes out under pressure and the radiator heats up but when I close the bleed value the radiator goes cold.
I have googled and followed lots of different suggestions but none have worked. I have bled the radiators, drained the system, isolated all the other radiators and tried balancing them. I don't have thermostatic values.

I'm at my wits end, any help / advice would be appreciated.

 

[dublin plumber]

take the radiator off the wall , and turn the valve into a bucket , turn it on and it will gush out water and some spluttering which is air trapped in pipe work ,run till hot , u may have to drain both valves , that works for me all the time

 

[Grego]

Thanks Dublin Plumber all sorted. It turned out that the return pipe was blocked on both radiators. I managed to unblock the pipes with some wire and now both radiators are working. The system did have inhibitor in but it looks like I'm going to have to add it again.
Once again thanks for the advice.

 

[stevetheplumber]

take the radiator off the wall , and turn the valve into a bucket , turn it on and it will gush out water and some spluttering which is air trapped in pipe work ,run till hot , u may have to drain both valves , that works for me all the time

you can get the same effect without dropping the rad shut both valves remove vent then draw from each side into a bucket held over the vent