Huh? I presume by that you are on communial heating...
Yes; you do need to get water out of them...
However; you should only bleed when the system is "off"... If you stop getting air out and still no water; then the system needs pressurising; if it is communial - Get your landlord to call in a plumber; it's their heating circuit; let them deal with it.
If its not communial (Which I must say I don't know many communial setups anymore) then you will need to ensure your boiler is topped up again - As above; you could just be lazy and get your landlord to call a plumber.
GasAid.co.uk
January 2007