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New water heater "moaning"

Posted by ctycdm (My Page) on
Thu, Dec 6, 12 at 12:13

Recently installed an A.O. Smith 50 gal. gas w/h. When the hot water is first run at any faucet or shower in the house, a humming moaning sound, like a fog horn in the distance, comes for a just few seconds, goes away, and then several seconds later a second slightly lower pitch sort of echos the first, then goes away. This only happens rigt when hot is used after not being used for a while. Not super annoying, but concerning that something may be wrong. Hooked up exactly to same existing waterlines and gas lines as the non moaning heater it replaced.

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RE: New water heater "moaning"

Just a couple of dart throws here. The noise may be expansion creaks from the line growing and rubbing across a structural member as it heats up. The hot water lines must have a little freedom to move or they will groan or snap when they are heated and again when they cool back down.

Also, water contains a certain amount of dissolved gasses(i.e., air). When the water is heated it drives them out in the form of bubbles which are released when you turn on the water. Try turning down the temp. a bit and see what happens.

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