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water hammer

Discussion in 'Irrigation' started by TPnTX, Jul 3, 2005.

  1. TPnTX

    TPnTX LawnSite Bronze Member
    Posts: 1,776

    I got this after reading another thread and realized I have a serious problem.

    I live out in the boonies so I can pretty much build/install whatever I wish. I did just that with my irrgation system.

    I tee'd off a 1 1/2 main, I didn't install a backflow valve or pressure reducer. I just gluded everything together and made a short run from the tee to a manifold where I put the valves. From that Manifold I made runs for 6 zones. It's not perfect but it works.

    Problem. I have water hammer when I shut off the shower.
    Looking back I think this began after I installed my system.

    The house is about 4 years old and the hammering didn't occur initially.

    What can/should I do?
  2. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    First off, just because your in the "boonies", doesn't mean you can do whatever you want. Says your in TX. That means that you have to either have filed designs and had inspections by your local govt./water purveyor, or you had a lic. irrigator install or approve your system. Second, backflow is state mandated and required. Lucky for you only a double check is required. And, now to help you, we would need more info. What is your static water pressure, what elevation changes occur from meter to house, etc. Water hammer from shutting off the shower shouldn't be a side effect of installing a sprinkler system, water hammer from the use of the sprinkler system is quite common. Give us some more info, and good luck.
  3. TPnTX

    TPnTX LawnSite Bronze Member
    Posts: 1,776

    there you go. I obviously didn't do my homework.

    Building this entire house only required one inspection from the county and that was for the septic system. (I didn't install that)

    I incorrectly assumed that I could install my own irrgation without inspection. I'll get a backflow installed at once.

    I didn't measure the static water pressure. It's not very good but I'll check it asap.

    The meter 600' away is a slightly higher elevation but with 12" elvation for slab/pad it goes back up. Its pretty darn flat in other words.
  4. Lumberjack

    Lumberjack LawnSite Member
    Posts: 180

    a back flow wouldnt be required on a well...but the irrigation system could stand to have one.

    as to the hammer you cut the line(s) at a nearby spot and install a tee pointing up...a piece of capped off pipe 1 to 2 foot long goes in... air gets trapped in the pipe and cushions the blows...
  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,686

    If there is 600 feet of distance between the house and the meter, then the supply line is the likely source of the hammer. Water hammer increases as the pipe length increases. The house should have a pressure reducing valve at the water's entry point, to take the force of the hammer, and to keep it from travelling further.
  6. Critical Care

    Critical Care LawnSite Bronze Member
    Posts: 1,654

  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,686

    Watts makes them, too. They are more like a 'shock absorber' than an arrestor, since the water hammer will still travel beyond the device, but hopefully reduced in intensity. The PRV will actually stop the hammer force from travelling downstream. The problem with the simple air chamber suggested earlier, is that the air will eventually be absorbed by the water, and the shock absorber effect will be lost.
  8. SWD

    SWD LawnSite Senior Member
    Posts: 989

    In the state of Texas, a homeowner does not need a license to install his/her own system. Additionally, inspections on homeowner systems are not mandatory unless it is a commercial site/domicile with more than one(owner's) family residing there - aka a duplex/apartment.
    What you refer to as water hammer may be a pressure problem in your house.
    Check for stopped vents in the roof, check your static pressure, check your gpm on the system vs your supply side, and the list goes on.

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