"Machine Gun" or "Thud" and a Weeping Toilet...oh my!

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by maxxis, Mar 22, 2009.

  1. maxxis

    maxxis New Member

    Mar 21, 2009
    Seattle, WA
    Hi all, long time reader, first time poster.

    I am having problems with one faucet in the house, which is the basement bathroom sink faucet and toilet. The faucet does one of two things randomly when the hot water is turned on:
    1. Sounds like a machine gun when you turn it on more than a 1/4 turn, or
    • It "thuds" and the stream goes to a slow trickle. The thud or "machine gun" sound comes from the wall and not the faucet itself from what I can tell.
    My house is 3 stories. I have a gas water heater (<8 yrs old). Attached to the water heater is an expansion tank with a valve at the top.

    [Side Note] From reading this forum, the first thing I learned was that I need to get some support under the expansion tank, which I plan to do asap.

    However, as seen in the pictures of my setup and of the street meter, I am not sure that I have a closed system. I don't see where I have a any sort of checkvalve except the one at the top of the water heater. As another sidenote, again using this forum, I replaced that valve about a year ago because it started spewing water (luckily I had my water alarm on the floor!).

    I attached the black hose in the picture and have it draining outside through an old pipe in the wall.

    Anyway, the house has 3 bathrooms and the kitchen. No other faucet/shower/tub exhibits this problem, except that faucet in the basement bath, and then it's only the hot water! That faucet is about 1-2 yrs old.

    1. What could be causing this problem?
    2. What should the expansion tank's gate valve be set too? I've tried opening and closing it but it doesn't seem to make a difference.
    3. I've also tried slightly closing the valve to the water supply to the house, without success. I even tried playing with the valve under the faucet to no avail.

    Separately, in case it has any relevance, my toilet in that same bathroom (american standard run of the mill two piece) was constantly running. About 18 mos ago, I bought a replacement kit at Lowes and it stopped the trickling noise. However, over the last few months, the tank has started trickling again. Is it normal for these to fail so often? I have had to turn off the valve to the toilet until I can find the root cause of the problem.

    TIA for any assistance!!!


    Attached Files:

  2. Dunbar Plumbing

    Dunbar Plumbing Master Plumber

    Apr 18, 2005
    Service Plumber, Outdoor Temperature Relief Owner
    Northern Kentucky/Greater Cincinnati Area
    I think I'm gonna cry.

    You got a loose washer on that faucet in question, easy fix.

    But who installed that water heater...
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  4. maxxis

    maxxis New Member

    Mar 21, 2009
    Seattle, WA
    Thank you for the advice!

    Oh, and it was installed when I bought the house in Jan 2001. What's wrong with it? I've entertained the idea of putting in a tankless water heater, but with the economy the way it is, I'm hesitant.
  5. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Nov 20, 2008
    Chicago Illinois Licensed Plumber
    Chicago, IL
    I am suprised the home inspetor did not gig the hose from the T&P Valve, and the gas piping.
  6. Redwood

    Redwood Master Plumber

    Dec 15, 2007
    Service Plumber
  7. C NUMB

    C NUMB Plumbing Contractor

    Jan 13, 2009
    NPR, FL

    According to the serial # it was not manufactured until April of 01 unless they changed how they date code.
  8. Gary Swart

    Gary Swart In the Trades

    Sep 1, 2004
    Yakima WA
    Aside from the problems others have pointed out quite well, PLEASE reconsider, restudy the wisdom of a tankless water heater. They cost more to install, operate, and maintain over the years than conventional gas heaters. There are other problems as well, but there is another section on this forum for tankless.:eek:
  9. seaofnames

    seaofnames DIY Senior Member

    Jan 25, 2009
    Mission, BC
    Is the expansion tank before the heater and after the city connection(with shut off)?
    Or is it after the heater? You'd need to put everything in the proper order as well as add a PRV to make it a closed system.

    That gas line(as mentioned above) is questionable. Did you have it inspected after it was installed?
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