I recently had by boiler serviced and a filter fitted to the feed to collect the gunge that can build up in the pipework. Since this was done I cannot get two of the downstairs radiators( kitchen and dowstairs toilet) to work without switching off one of the upstairs ones! Ive tried bleeding the rads and increasing the water pressure intake to the boiler from 1.5 to 2 bar, but nothing has worked.
Any ideas gratefully accepted!!