Posted by jtown on November 12, 2001 at 20:28:25:
In Reply to: more questions posted by jennifer on November 12, 2001 at 18:34:50:
Safety valves are screwed into the boiler, or other pressure vessels. It has a discharge pipe that blows water onto the floor normally, or your sink. Modern ones have a little lever that you can lift to test it. You could have an old one with a long arm with a weight on it that can be moved to change the leverage and thus the opening pressure. Do your radiators have two big pipes going to them? One down low on one side and one high on the other? A sight glass is a piece of glass tubing next to an expansion tank or a steam boiler so you can see the water level. It sounds like you have a try cock to let you know that the water is high enough. Do you have a pipe that comes out of the tank up high that goes outdoors or to a drain? Bleed water out to the try cock on the tank so there is room for expanding water. The weight of this water should push the air out of your radiators. Just add water after bleeding a bunch of air. A pump would be in the piping near the boiler, have an electric wire to it. My guess is that you are gravity and are fine as long as the leak was above normal water levels. The water shouldn't get to the top of the expansion tank normally. When the water gets hot it expands into the tanks volume and then shrinks when cooling.