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Question about my new sprinkler system

Discussion in 'Irrigation' started by gdeangel, Oct 14, 2006.

  1. gdeangel

    gdeangel LawnSite Member
    Messages: 37

    Hello - I just had a pro install a new lawn sprinkler system for a new lawn at my home. I noticed that when several of the zones shut down, there is a loud clunk from my basement where the plumbing ties in... is that water hammer and is it normal or should I be concerned. He has 8 zones to do about 1/4 acre. The main backflow is run off my water supply BEFORE the pressure reducer for my indoor plumbing. I think my pressure is something like 100 PSI at the spicket (after the PRV).

    Second, I hear a pulsing noise, like a clicking, coming from the area of the valve box when some of zones are running - I think its one or two with rotors.

    And advice as to whether I need to worry, or what fix is in order?

    Also - a design question - there is a strip about 15 feet wide along side of my house. I asked him to run the heads about 8-10 fee off the side of the house, as I plan a garden bed along the house... He ran one row of 360 degree heads down the middle of the 15 foot span. They seem to be about 10 foot radius, which is the head spacing (five heads - this is one of the zones with the "clunking" noise when the zone closes).

    Thanks in advance!
  2. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    This seems to be a recurring thread. I'll let the basement dwellers (JK... those on the site that routinely make POCs in basements) answer.

    The "clicking" noise may be the activated solenoids. Some are loud and others are fairly silent. It's a common occurrence.

    A "pulsing" noise may be the water rushing through a valve. Sometimes a valve isn't open all the way (if it has flow control) or a diaphragm isn't opening fully.

    I don't understand your question. Are you questioning the sprinkler head placements or the number of heads in relationship to basement noise?
  3. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    What type of pipe and size provides the water in your basement?
  4. gdeangel

    gdeangel LawnSite Member
    Messages: 37

    So I gather these noises - flow control partially open or whatever - are nothing to worry about?

    The pipe in the basement is 3/4" copper from the water line to the backflow - about 15 feet length... and the valve box is not much farther. In the ground is the black flexible type pipe (not pvc).

    The question about the 15 foot strip is whether the placement is good. In looking at "design it yourself" tips, I got the impression that there should be a second run at the edge of the property to make complete overlap of the sprays... and also whether it's good design to run the heads down the center like that spraying toward the house and the garden (which will have seperate drip irrigation.

    Thanks for the help,
  5. Lawnworks

    Lawnworks LawnSite Fanatic
    from usa
    Messages: 5,407

    Sounds like he put them right where you asked him to! You should be able to convert them to spray 180 degrees very easily. Some vans have a nozzle you can just twist to adjust.
  6. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    Water hammer can damage piping, fittings and other parts of a water system. It all depends on the material's strength relative to the shock wave created by the water hammer.

    Water hammer associated with homes that run copper or other metallic piping to the building and then is split off to PVC and/or PE is often common. The main reason is that your domestic service lines are usually not engineered for irrigation systems. Their smaller diameters are solely for service to the house and its appliances. Often the speed of the water through these pipes exceeds 5 ft/sec and often goes up to 11-12 ft/sec because they are designed for the house where automatic valves (other than washing machines, ice makers, etc.) usually don't come into play.

    Even if the piping for the irrigation system is calculated correctly water hammer can still occur because the initial push of water from the domestic connection is flowing too fast (not to be confused with PSI). One recommended method of curtailing water hammer would be to install a master valve ahead of your zone valves and then installing a water hammer arrester upstream within 6" of the master valve. The master valve must shut down prior to your last zone valve closing and then any associated water hammer is dampened by the arrester before it has the chance to get back to your domestic supply through that 15' pipe.
  7. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794


    Every plumber I know just runs 1/2 or 3/4 Wirsbro or Copper without any thought as to flow requirements.

  8. gdeangel

    gdeangel LawnSite Member
    Messages: 37

    It seems this ideal about installing an arrestor upstream of the master valve (I think there is already a master valve installed) would solve the problem if the hammer were occurring when everything shuts down. What I have is something like this:

    /start 1/
    /stop 1-start 2/
    /stop 2 - clunk from pipes in basement - start 3/
    /stop 3-start 4/
    /stop 4-start 5/
    /stop 5 - clunk from pipes in basement - start 6/
    .... etc.

    The clunk is not coming from the household piping, but it is so loud coming from the service pipes in the basement that you hear it in the whole house - it sounds like someone trew a baseball against the wall of the house.

    As to the design, my question was whether there should be two rows of heads. Yes I asked him to move them off the edge of the house, but thought he would keep the other row along the property boundry line. It's not a big deal - I'm not going to redo it now unless the grass really dies next summer... I just wonder whether it's right.
  9. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    They usually run what the building's architect puts down on the prints. On a home there is little concern about irrigation from architects. On major complexes you will see a separate irrigation supply. I'd suggest that anyone having a house built get with the architect and have an irrigation supply specified. Maybe a little more expensive at the start of things but well worth it in the long run. Probably 95% of the GPM/PSI/water hammer problems would be solved before they even start. :)
  10. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    I just relaying what people much more informed about water hammer suggest. :)

    Turn the flow controls down a little on the valves that are causing the "clunk." No flow control valves? Oops... :dizzy:

    Classic water hammer symptoms.

    The only time you'd see just one row of sprinklers down the center of a zone might be in an extremely narrow area. You should of worked this out with the contractor prior to his installation. There might have been miscommunication about your garden plans.

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