Posted by jtown on February 05, 2000 at 06:12:11:
In Reply to: Water still in Radiator posted by Tom G on February 05, 2000 at 05:45:54:
There is no "water pressure". It is like a pressure cooker on a stove. There is no pressure (actually, no more than the surrounding atmospheric) and you boil the water making steam. When the steam makes the air vents hot they close. Boiling more steam makes the pressure go up. When it cools the vents open and allow the pressure to drop back to atmospheric. The air venting scheme is to counteract the vacuum that would build and leak air in and then you wouldn't heat with air in there. Get rid of the bouncing water line by skimming the surface, or live with wet steam blowing out where it can. Your waterline should just slowly and steadily drop while boiling.