radiators not working

[ruth0007]

hi
my upstairs rads are working ok but downstairs are all cold ive turned the upstairs ones off but this doesnt help
sometimes the pipes leading to each rad gets hot but not the rad itself,
please help im froze

 

[oilman]

There is air in there somewhere, try bleeding the pump.

 

[ruth0007]

looked at the pump cant see a screw
thanks for helping!

 

[jpm321]

it the big screw on the front in the centre about size of 5p

 

[ruth0007]

thanks bled it but no air came out
dont know what to try now