Water Heater thumping noise

PJ Flocker · Oct 27, 2007

I have had my (75 gal, new house) water htr for about 4 years and I have noticed a thumping noise (it is easy for me to hear because it is in the wall right beside my master toilet area) almost every time I use the master shower and when I run the hot water in one of the sinks. It sounds like the noise it is coming right from the hot water heater and not any pipes in the walls. My plumber nor any contractor has been able to figure out what it is. Any thoughts??

Thx!! PJ

Patrick88 · Oct 27, 2007

Is it gas, oil, or elec...? Does it have and expansion tank on it? Do you have a pressure reducing valve on your main?

Sponsor · 2022-01-29T12:20:58-0800

Markts30 · Oct 27, 2007

Expanding pipe?
Hot water running through water or waste pipe causing it to rub on framing members inside the wall - noise is amplified by the drywall surface...

PJ Flocker · Oct 27, 2007

Yes...sorry it is gas. I don't believe it has an expansion tank...how would I know? And, yes, we have a pressure reducing valve on the main...

THX

Dunbar Plumbing · Oct 27, 2007

If you haven't drained the water heater yearly and it sounds like monkeys drumming whenever there's a quick shutoff of water....it is sediment bouncing around in the bottom of the tank.

Toolaholic · Oct 28, 2007

Agree with Rugged ,Let's call it MUD JUMPING

drain it with a hose for 5 minutes

Herk · Oct 28, 2007

I don't know what part of the country you're in, but here in Idaho, the water is very hard. Soon after installation, a gas water heater is likely to have a skin of lime on the bottom, and as it heats gas bubbles form under it, and it pops. It can sound like gunfire. It won't do any harm - except for the sound. It's much more prounounced as the heater gets older, and although draining may help, it may not solve the problem. Unless the heater has a hand-hole cleanout, which is a rarity in residential heaters, you're probably stuck with it.

If your part of the country does not have hard water, it may be, as previously stated, flushable.

Toolaholic · Oct 28, 2007

Thanks' Herk

Had No idea , Here in N. Ca. We don't have that problem.

Another VOTE to, " MAKE EM POST THEIR LOCAL. "

Don't make Me break any more little fingers !!

Gary Swart · Oct 28, 2007

This may or may not be the solution to the thumping problem, but if you have a pressure regulator valve, then you should install an expansion tank in the cold water supply line. When water heats, it expands and has to go somewhere. A PRV has a check built in that prevents the expanded water from being absorbed by the city main. This causes the pressure inside the water heater to rise rapidly and to a very high level. So high that it usually trips the TP valve on the tank. The expansion tank absorbs the expansed water.

Toolaholic · Oct 28, 2007

Good point Gary,but He didn't mention the t p dumping!

Jadnashua · Oct 28, 2007

I thought I'd read that a PRV when it gets worn some can sometimes make that noise under excessive pressure. Regardless, if you have a PRV, you must install an expansion tank...they go hand in glove, you have one, you should always have the other.

hj · Oct 28, 2007

thump

Do you have a retrofit hot water circulating pump on the hot water outlet of the tank?

PJ Flocker · Oct 28, 2007

Thanks everybody!!

Sorry...my location is Phx, AZ. So, as to the re-circ pump..I don't have on of those, although I wish I had one...it takes forever to get hot water to my kitchen. Anyway, I do have hard water where I live in Phx., but I have a soft water system since the house was built...
Also, it doesn't happen after a quick shut off...usually after the hot water has been running for maybe 5 minutes or so...
So, I think from all your comments my solution is to flush, check my TPV and the expansion tank...

Thanks everyone!!!

PJ

hj · Oct 29, 2007

noise

The noise could be the water meter sound being amplified by the water heater.

Alectrician · Oct 31, 2007

PJ Flocker said:
Sorry...my location is Phx, AZ.
PJ

Hey!

I'm in Phx and have (maybe) the same issues in TWO houses. Ruud brand 40 gallon.

No expansion tank, never used them before.

When I turn on the cold water somewhere, the gas WH occaisionally makes a nice little pop. In the other house it's more of a BANG .

Mine is not the rumbling sediment sound, just an pop or bang occaisionally

Must be the heat here.

Water Heater thumping noise

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