Manifold Advice

Discussion in 'Irrigation' started by blueline, Apr 16, 2008.

  1. blueline

    blueline LawnSite Member
    Posts: 8

    I need some advice on my manifold. I used the Dura manifold. My problem is that there is too much lateral pressure and the plastic threads on the left side of the Dura are leaking. I tried to retape and tighten, but the threads pop loose and the leak is worse now.

    Any suggestions as to how best to do this? The main is 1 1/4" poly. I'm thinking about scraping the Dura manifold and going PVC. Is that the preferred way? The valves are threaded.

    Also, should I throw couple of 90's on each end of the manifold so that the manifold isn't directly inline with the main?

    I attached a couple of pictures. The pump side is the right side of the manifold; the left side continues to another manifold in the front yard.

    Any other advice would be appreciated.



  2. poiuy qwerty

    poiuy qwerty LawnSite Member
    Posts: 57

    I have never used the dura manifold but i have heard nothing but bad things about them. From what i hear you can not tighten too much or it will leak ( hand tight then a 1/4 turn with a wrench) Also I am not sure you are to use tape on them. I would scrap it and go with a PVC manifold, just to be safe.
  3. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,720

    Hard to believe a pump has enough pressure to damage a manifold. If those are MPT x barb valves (which I don't use) your best solution might be to combine sch 40 slip fittings with sch 80 unions. Same basic functionality as what you already have, but several notches stronger than the Dura manifold you picture.

    You'd get the sch 80 unions in both slip versions and threaded versions, and swap the parts around to get slip x FPT unions.
  4. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    I have used hundreds of the DURA tees with little problems. Never the full one piece manifold like that though. always the individual tees. Problem more than likely is that things are not straight - mainline or laterals. this is causing stress and leaking. You should not need thread tape either. Check and see if the o-rings are cracked or out of alignment.
  5. bobw

    bobw LawnSite Senior Member
    Posts: 807

    Spears makes similar fiitings to Dura and with a much beefier 0-ring that alleviates some of the issues with lateral stress and over-tightening.

    Undo all your fittings and then re-do them. Hand tight + half turn. Make sure you keep everything in alignment.
  6. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,799

    My guess is since your manifold is sitting in the open air like that, the water hammer from your pump is tweaking the manifold over and over again, until one of the fittings started to leak.

    Change it for PVC, and put it in a box :)
  7. blueline

    blueline LawnSite Member
    Posts: 8

    The big issue isn't the pump pressure. It is the lateral pressure of the main physically pushing on the manifold assembly. There is a slight curve in the main there, so it isn't quite straight. That is why I may bury the main lower, add some 90s to each end of the manifold to raise it up above the main. That will allow me to adjust the angle of the manifold to take the pressure off of it. Anyone disagree with the idea of adding the 90s to make it more adjustable to relieve the lateral pressure?

    The whole thing will be in a box and the pipes buried to put the hammer on the hammer....

  8. Dripit good

    Dripit good LawnSite Bronze Member
    Posts: 1,081

    Why in the world are you using regular wire nuts & tape? Use the proper King connectors to finish your wiring. Your splicing will not last very long. :nono:
  9. blueline

    blueline LawnSite Member
    Posts: 8

    I did that temporarily until I get the heads on. The splices will be above grade, so I don't anticipate the box filling with water with the drainage. Do I still need to worry about it?
  10. Dripit good

    Dripit good LawnSite Bronze Member
    Posts: 1,081

    Yes..... Moisture will find a way to get in there and deteriorate your splices.

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