Radiators downstairs wont heat. If I draw water through into them I can draw hot water into them but they don't heat with the central heating on. Its an indirecet f and e system. Is this an airlock or something else?
See last answer but if you can hear water run through rads probably not pump.
Could be one radiator getting all the heat run heating and check all rads turn down those that heat first or turn down all upstairs rads and see if downstairs works.
If not turn off all radiators except one downstairs this will send all heat to that rad and prove flow ok do this with all rads one at a time to reestablish water flow.
Then turn on rads one at a time to allow flow to each rad.
Failing that system may need bleeding and rads balancing.
Sounds like a circulation problem probably the pump not working it should be possible to remove the cover in the middle of the pump and then with a screwdriver try to spin the pump manually to see if this frees it up to work again