Master Valve with poly main, or just a poly main?

Discussion in 'Irrigation' started by rvsuper, Aug 2, 2003.

  1. rvsuper

    rvsuper Senior Member
    Posts: 930

    If you guys use poly mainlines, do you use a master valve also so there isn't always pressure at the poly main, or do you just have constant pressure on the poly main? I always use PVC, and this question was just out of curiosity. I would think that a poly mainline would be able to hold constant pressure?

    Any comments?
     
  2. greenworldh20

    greenworldh20 LawnSite Senior Member
    Posts: 659

    always use master valve with poly main...poly doesnt hold pressure as well as pvc.

    just my .02
     
  3. rvsuper

    rvsuper Senior Member
    Posts: 930

    Brain,
    Have you seen systems with a poly main without a master valve?
     
  4. JeffY

    JeffY LawnSite Senior Member
    Posts: 324

    I'll always use a master valve when using a poly main. Although I have not seen one for myself, I've heard few stories in the local area about poly main pipes bursting without master vavles. They would fix it and it would burst again in another area.
     
  5. rvsuper

    rvsuper Senior Member
    Posts: 930

    Jeff,

    At what pressure would it start bursting? I am just curious because I have never used a poly mainline before, all PVC.
     
  6. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    I've done the poly mainline with no MV and have had no probs. But you have to get the higher rated poly. They make a poly for mainline applications.
     
  7. JeffY

    JeffY LawnSite Senior Member
    Posts: 324

    We use the Eagle poly (PE 3408)that's rated at 100 psi, but there are two other Eagle types the PE 2406 and PE3408 (note the difference..no space) that are rated up to 80 psi. It's quite possible that these companies were running into the lower type pipes on the commerical properties that were causing the pipes to burst.
     
  8. turfman59

    turfman59 LawnSite Senior Member
    Posts: 801

    I cant beleive my eyes.

    poly doesnt hold pressure so you need a master valve.

    I have worked on systems that have been in the ground for 20 years and longer with no master valve, with no probs. I think that the potential burst problems would be with the fittings not the pipe. Just my 3 cents worth, here at aqua turf we always give you more
     
  9. greenworldh20

    greenworldh20 LawnSite Senior Member
    Posts: 659

    i have seen many main lines burst....they were poly mains...just my.o2
     
  10. rvsuper

    rvsuper Senior Member
    Posts: 930

    I can't believe this! How much pressure are laying in those mainlines that make them burst??? Was it under the 100 psi rating??? The highest pressure here that I deal with is about 50 psi, will that cause them to burst?? Fill me in about this, I'm just curious on how these poly mains do.

    Alex.
     

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