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Solutions for pipes rattling inside when system is starting up and switching zones

Discussion in 'Irrigation' started by Broker, Jul 21, 2005.

  1. Broker

    Broker LawnSite Senior Member
    Messages: 382

    Do any of you have solutions for the pipes in the basement that rattle when the zones first start up. This has been a problem for the past couple of years for our plumber and we are finally starting to make some progress. Shock arresters, expansion tanks, regulators and dual checks seem to solve the problem after you find out which one is needed. What have you guys found throughout the years?
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,592

    Pressure regulators for the house plumbing is the usual setup, with solid bracing for the sprinkler supply plumbing, especially when the flow velocity is high. (Meter in basement, sprinkler supply teeing off right after the meter) - On the system itself, it might take heads with check valves all around to prevent higher-velocity flow at startup. There is a 'specialty valve' made that would address this specific situation, when used as a master valve, but it's big bucks, and for pipe sizes larger than residential sprinkler systems.
  3. Ground Master

    Ground Master LawnSite Senior Member
    Messages: 505

    1. pressure regulator
    2. upsize the pipe in the basement. i.e. if your supply line is 3/4" use 1" for your sprinkler mainline staring in the basement.
    3.use slow closing valves, i.e. Rainbird PEB serie
  4. Broker

    Broker LawnSite Senior Member
    Messages: 382

    What we have found that works..

    If the house lines are banging with the system starts up, then installing a dual check backflow preventer on the house line works great.

    If the sprinkler line is banging when the zones start up, then a shock arrester or expansion tank will usually will take care of it.

    If the backflow is banging when the sprinkler starts up then a regulator will take care of it.
  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,592

    I'm curious, are you using one inch poly for these residentials? And no three-quarter? Heads with check valves, like I-20's? What range of static pressures do these banging systems have? I try to fasten the indoor lines tightly enough that the bang is more of a bump. Mileage can vary.
  6. Broker

    Broker LawnSite Senior Member
    Messages: 382

    the range of static pressure for when the house lines are rattling start around 70psi. Keep in mind that it is the house lines and not the sprinkler copper line. And that it is usually only a problem on homes with certain builders. Such as the mass production type of builder never a problem on the more custom type of homes.
  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,592

    I would think that a PRV would prevent the hammer from going beyond it, so I would always feed the house line through it, and brace it and the nearby house pipe.

    I don't see startup banging in the sprinkler system so much as shutoff banging. I sometimes wish they still made valves with adjustable closing speed, especially when I find more flow than when I tested the supply with that Toro flow and pressure gauge assembly.

    Since I do use 3/4 poly for a lot of zone piping, I wonder if that resists the opening flow enough to make a difference in startup banging. (I'm using Irritrol valves)

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