Problem with Thorn boiler. Had a problem with heating system, so checked pump, pump worked ok! but no water getting to it. opened valve on feed side but no water there. Checked header tank-OK!Checked water feed to boiler - OK! .Opened drain cock on Boiler only limited water came out then stopped. It appears that something is stopping the flow of water through the boiler, it is not getting to the drain cock or to the output side of the boiler then on to the pump, any ideas.
Kev
Kev