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Schedule 80 Versus Schedule 40

Discussion in 'Irrigation' started by MEXANDME, May 20, 2013.


    MEXANDME LawnSite Senior Member
    Messages: 396

    I intend to start using Sch 80 TOE nipples for both the suction and discharge lines out of above ground irrigation pumps. Can I use Sch 40 slip x slip couplings to transition from 80 to 40 or should I use Sch 80 couplings as well?

    Thanks / Regards,

  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,246

    Don't use PVC on the suction side, or either side, really. Metal takes heat better than will plastic.

    MEXANDME LawnSite Senior Member
    Messages: 396


    My problems have come primarily from Sch 40 Male Adapter failures. Are you suggesting that I use a galvanized nipple out of the pump, then a galvanized threaded coupling, and then a Sch 80 TOE nipple?

    Thanks for your willingness to share!!!!

  4. bcg

    bcg LawnSite Bronze Member
    from Tx
    Messages: 1,865

    Everything attached directly to the pump should be galvanized. If you want to skimp some, which I wouldn't suggest, skimp on the intake, not the outflow of the pump. Using PVC on the outflow side of the pump will fail.

    About a 12" galvanized nipple should be fine, and then you can go to whatever Sch or Class of PVC you'd like. Just need to get rid of the heat first.
  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,246

    Since I never used foot valves, it was an easy call to spec a short galvanized nipple on the suction side, with a spring check valve leading into it.
  6. Stuttering Stan

    Stuttering Stan LawnSite Bronze Member
    Messages: 1,504

    I have used both galvanized and sch 80 for intake and output. No problems with either option.
  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,246

    There are issues for some folks with suction leaks where plastic threads into the pump.
  8. 1idejim

    1idejim LawnSite Fanatic
    Messages: 11,094

    Use brass
    Posted via Mobile Device
  9. AI Inc

    AI Inc LawnSite Fanatic
    Messages: 26,607

  10. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,246

    Brass is most correct, but galvanized isn't a horrible second choice. Since I sometimes included a large ViewFlo strainer on the outlet, I would have a 12 or 18 inch pipe coming up from the pump case, and it had to be metal, for the support I wanted for the strainer.

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