central heating problem

gefpm

i have a 2 story house with a closed circuit heating system in it. 2 of the 4 rads upsatirs have not been workin recently so i decided to bleed 1 of them. when i did this there was a slight smell of gas coming from it but there was plenty of air to release also. i could hear the rad filling up with hot water instantly and it became hot. then when i went to the second larger rad i opened the screw and only a small bit of air came out of it and then it stopped. there was no sign of any water then to spill out from the rad so i then closed the cap. when i got down stairs i noticed that the boiler had turned it self off and the "Bar" level was at 0. I then went back upstairs to the hotpress and opened the valve beside another pressure meter that also showed 0 and when opened the water started to run into the boiler down stairs, the pressure rose again and the boiler fired up again. now there seems to be water in all the upstairs rads but they are all now cold when the heating is turned on.
I also need to know what should the "Bar" pressure be at for this terraced 2 bed house. and if you could enlighten me as to why the upstairs rads are now all cold it would be great.
thanks.

JamesM

What you have done is correct. The "Bar"should be about 1 to 1.5
You may now have an airlock in the system. If the downstairs rads are off, turn them on. If they are on, try turning them off. Different combinations may push the air out of a pipe into a rad.
Jim.