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Patrick, General Contractor
Category: Plumbing
Satisfied Customers: 2429
Experience:  30 years commercial construction and 23 years house remodeling projects
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My gas water heater is making a loud banging noise several

Resolved Question:

My gas water heater is making a loud banging noise several times in a row then stops. I feel vibration in the flu vent when it is banging. It is almost as if there were a woodpecker pecking in the flu, but it sounds mechanical. The noise stops for 30 seconds or so then starts again. It doesn't sound like it is coming from the tank. I can't find anything else wrong, but I ran out of hot water in the tub. We have never run out of hot water before. What can cause this?
Submitted: 7 years ago.
Category: Plumbing
Expert:  Patrick replied 7 years ago.
Banging is typically caused by sediment build up in the bottom of the tank that is causing irregular heating of the tank bottom. The sediment or scale creates an insulating layer that basically heats up and explodes creating the banging and sometimes popping noise inside the tank. You can shut off the gas and open a hot water faucet and drain the tank through the drain bib low on the tank, hook up a hose , and do some repeat flushing to get rid of any sediment that is loose. Unfortunately, by the time you start hearing this, the scale or sediment has built up pretty well. Good luck. If this has proved helpful please remember to hit ACCEPT, otherwise I do not receive credit. Thank you.

Edited by Patrick on 3/8/2010 at 5:48 AM EST
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