Water Heater thumping noise

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by PJ Flocker, Oct 27, 2007.

  1. PJ Flocker

    PJ Flocker New Member

    Messages:
    6
    Location:
    Phoenix, AZ
    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??:confused::rolleyes:

    Thx!! PJ
  2. patrick88

    patrick88 Plumber

    Messages:
    836
    Location:
    Webster Ma.
    Is it gas, oil, or elec...? Does it have and expansion tank on it? Do you have a pressure reducing valve on your main?
  3. markts30

    markts30 Commercial Plumber

    Messages:
    630
    Location:
    Phoenix, AZ
    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...
  4. PJ Flocker

    PJ Flocker New Member

    Messages:
    6
    Location:
    Phoenix, AZ
    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
  5. 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.
  6. toolaholic

    toolaholic General Contractor Carpenter

    Messages:
    874
    Location:
    Marin Co. Ca.
    Agree with Rugged ,Let's call it MUD JUMPING :D drain it with a hose for 5 minutes
  7. Herk

    Herk Plumber

    Messages:
    547
    Location:
    S.E. Idaho
    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.
  8. toolaholic

    toolaholic General Contractor Carpenter

    Messages:
    874
    Location:
    Marin Co. Ca.
    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 !! :mad:
  9. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,335
    Location:
    Yakima WA
    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.
  10. toolaholic

    toolaholic General Contractor Carpenter

    Messages:
    874
    Location:
    Marin Co. Ca.
    Good point Gary,but He didn't mention the t p dumping!
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,937
    Location:
    New England
    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.
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,529
    Location:
    Cave Creek, Arizona
    thump

    Do you have a retrofit hot water circulating pump on the hot water outlet of the tank?
  13. PJ Flocker

    PJ Flocker New Member

    Messages:
    6
    Location:
    Phoenix, AZ
    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 ;)
  14. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,529
    Location:
    Cave Creek, Arizona
    noise

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

    Alectrician DIY Senior Member

    Messages:
    689

    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.
    Last edited: Oct 31, 2007
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