Posted by jtown on October 06, 2001 at 18:45:56:
In Reply to: Re: hotwater/expansion tank questions posted by Chadwick T. Morgan on October 06, 2001 at 06:21:34:
If you have the old type expansion tank without a bladder and you really have air then lose it, and not water, then the leak is at the surface of the air. You could have a pinhole in the tank that acts like Gore-Tex passing gas but not liquid. If you have a gauge glass on the tank, the top fittings exposed to air might leak. Some tanks have a drain cock that has a bleeder fitting on them. Opening the bleeder allows air to go up a tube to the air space to break the vacuum when draining. The cap on the bleeder can be leaking. Shut off the feed and valve off the tank. Open the drain and bleeder. If you have no bleeder you can pull the drain cock and put a piece of tubing into the top of the tank to get the water to drop. Close up the tank and open feed. Goop the bleeder cap if you need to with non-petroleum goop if there is a rubber gasket. If you ruin it, you needed a new one anyways. The air will dissolve into the water over a long time necessitating the draining every few years.
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