No distance on rotors! Freaking out!

Discussion in 'Irrigation' started by 5starlandscaping, Aug 22, 2006.

  1. 5starlandscaping

    5starlandscaping LawnSite Member
    Posts: 21

    I just installed a 1 zone with 7 Hunter pgp rotors. I may be pushing it with 7 heads but the distance is still only about 60% of what I am used to seeing with these heads. My employee and I held down two of the heads to see if this would help with the pressure and it didnt so I think I may have a flow problem. I cut into a 3/4" galvanized line with a compression tee about 2 foot off the house meter. Then went through a 1" PVC "check valve" then into a 1" shut off ball valve and then into my 1" irrigation valve, all within 15 ft of the meter. FRom the rotor heads back I have 20 ft of 1/2 " then 10 ft of 3/4" which runs into my main line which is 20ft of 1" pipe back the irrigation valve.
    Maybe I should not have used 1/2 pipe from the heads? I am thinking the 20 ft. of 1/2" pipe may be reducing my flow but I have done this before with no problems. Tomorrow I am going to check the "pvc check valve". I may replace it with 1" brass check valve which looks a a hole lot smaller and seems to have less resistence on the springs. Maybe this will help out my flow. If this doesnt work I may have to fudge and move heads around because I am going to have a few bad dry spots.
    I also noticed that the inside of the 1" ball valve looks like a 3/4 opening. Could this be causing a drop in flow? Maybe I could use a 1 1/4" ball valve and reduce down on both sides to 1". I am just baffled. I have been racking my brain to try and figure out whats the problem. Can any of you guys shed some light on what may be causing the problem?
     
  2. Hank Reardon

    Hank Reardon LawnSite Senior Member
    Posts: 599

    Did you check the gpm and pressure prior to installing? It sounds like your problem is lack of planning.
     
  3. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,035

    A single head running from 1/2 inch shouldn't be a problem. Consider renozzling the heads before you go replumbing things. (You should have a genuine backflow preventer, and not just a check valve)

    But really, you should have done a flow-and-pressure test first, before you designed the system. Another flow-and-pressure test couls have been made at the system connection.

    With galvanized (or really any) pipe, it pays to know, and not just guess. Too many variables, especially rust buildup inside the galvanized.
     
  4. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    What size nozzles are currently in the PGP's?
     
  5. DeepRoots

    DeepRoots LawnSite Member
    Posts: 37

    5starlandscaping.
    I've worked in Valdosta a good bit (weird seeing someone else within 20miles on a large website).

    Anyway, a 3/4inch galvanized line should be pushing what? 10-12gpm?
    If this is an older house, and older pipe, I'd have to expect more like 8gpm.
    and you are trying to push up 7 Hunter PGP's.

    Of course us in the internet world have no idea what the pressure and flow are from this pipe as we aren't on the jobsite, and didn't do the preliminary checks.
    Re-Nozzling *might* help, but a smaller nozzle may be unsatisfactory, and may not produce the desired result.

    If that doesn't work, you're screwed.....
    no seriously, try to make it work, if it doesn't there is always doing the 'right thing' and telling the customer you screwed up, and you need a larger water hookup from the city.

    Drew
     
  6. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    How about taking the time to fix it by splitting it into two zones? Fix it right now, rather than rig it to kind of work. This will save you headaches down the road.
     
  7. Az Gardener

    Az Gardener LawnSite Gold Member
    Posts: 3,899

    You could always go to MP rotators, they should work fine.
     
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,035

    With the quoted radius (I'm guessing 20-25 feet) I expect the nozzles could be reduced a couple of sizes with good results.
     
  9. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Actually, according to the charts, 8 GPM and that's based on new, unobstructed pipe.


    I'd expect less. :)
     
  10. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Why would you use 1/2" pipe on a sprinkler head that is 3/4" NPT opening?
     

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