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PVB and Noise

Discussion in 'Irrigation' started by Aik, Aug 4, 2005.

  1. Aik

    Aik LawnSite Member
    Messages: 2


    I have a Watts PVB device for my irrigation system. For the past 2 years, it's seemingly functioned without a problem. The city recently replaced my water meter (it was a routine upgrade). The next day, when my irrigation system came on, there was loud hammering sound coming from my plumbing that leads to the PVB. For the next few weeks, there was no hammering sound when the irrigation system ran. Yesterday, I had my PVB tested and certified. As the plumber was doing the test, the same hammering sound occured. Then, the first time my irrigation system started after the test, the hammering sound occured again.

    I'm trying to figure out what's causing the hammering. My best guess is that I'm getting water hammer when the PVB activates. And I'm also guessing that it activated the first time because there was air in the line after the meter was replaced. And it activated for obvious reasons during the test. I don't know why it would have activated following the test.

    Any advice or insight would be greatly appreciated.

  2. SprinklerGuy

    SprinklerGuy LawnSite Bronze Member
    Messages: 1,778

    Check to see that they turned the valve at the new water meter back on all the way.....Plumbers and city workers are notorious for that.
  3. dozerboy

    dozerboy LawnSite Member
    Messages: 5

    Does the noise happen when the valves open or close? If it happens when they close bad news. Electric valves close very fast and if the water in your system is running too fast (ft/s) it will cause water hammer. Water hammer tends to break things. If it is happening when the valves open it is probably just air, which normally doesn't break things(but can get annoying)
  4. Aik

    Aik LawnSite Member
    Messages: 2

    It happens when the valves open, when the system is just starting up.

  5. Broker

    Broker LawnSite Senior Member
    Messages: 382

    try a pressure regulator on the inside irrigation line
  6. dozerboy

    dozerboy LawnSite Member
    Messages: 5

    I had one that was doing the same thing and I tried putting on a pressure reg. which was no help. I also installed f/c valves but hads to turn them down so far that it was affecting the noz performance. What finally worked for me was a water hammer arrester right after the pvb.

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