Shawn

Well, I had someone out today to look at it. He turned it on and off a few times (and of course the sound didn't happen while he was there) and said the same thing as the two contractors I spoke with previously-- there's no danger and no immediate need to replace the heater. He said he thought it was probably the baffle (in the flue) making the single bang sound when the unit shuts off. He said he made a service call to someone else for the same reason yesterday and also told them it's not dangerous, just a sign the water heater is getting old or hasn't had proper maintenance/draining sediment etc. and that it's fine to wait until you actually "need" to replace the unit before shelling out the cash for a new one. The water heater is actually 4 years old, not 3, I doublechecked the records on that. And Les, I'm in Macomb County (north of Detroit).

Gas. Sorry, forgot to mention that.

Hi from Michigan! [^] My 30-gallon Kenmore water heater is three years old. Last week it started occasionally making a noise it's never made before: a single, loud, metallic bang about two seconds after shutting off. It's done it maybe three times in the past week. Does this seem to you like something dangerous or unsafe? Oh, and if it's any help, the first time it made the noise was just a couple of hours after some workmen were up in the attic above the water heater, so I'm wondering if the noise could be related to something they might have moved or dislodged up there? A couple of servicemen I called said they didn't think it was anything to be concerned about, but I find it strange that it never made this sound before last week but has done it at least three times since then. Any ideas you have would be welcome, and I really appreciate you taking the time to reply!