I live in a block of flats which share a communal boiler (theres no boiler in my flat) each flat then has a heat board. I went to turn my heating on for the first time since about March this year and none of the radiators worked. So I bled them and only two out of four actually had any water and bubbles come out the others seemed like there was no water in them. However after bleeding them I tried again turning 1 radiator on at a time, one of the dry radiators finally sounded like it was filling with water but even though I have it set to the maximum temp on the radiator and the thermostat up high it's barely warm the top of the radiator is cold while the bottom gets luke warm. The other 3 radiators don't do anything. What could be the problem? Also if I called someone out to look at it would they need access to the boiler room for a problem like this?
Any help would be great!