Well I tried all sorts, and am still at the same state as before.I have tried what you said and ended up with none of the radiators working,so I bought a sludge remover,and I now still have the downstairs 3 working but not the upstairs.I am going to take the radiators off and flush them through...
I have a parkray fire but have problems with my radiators.The upstairs,of which there is 3 and on gravity feed are all cold,even with the pump on they dont work,any ideas.I have drained the system and still no results.The pump works for the downstairs ones but all the upstairs are cold.