Flow Capacity of 1" Orbit and other Valves

Discussion in 'Irrigation' started by Steve P, May 30, 2012.

  1. Steve P

    Steve P LawnSite Member
    Messages: 14

    I have a marginal system that I am trying to fix. Pressure is ample and there are not too many sprinklers, at least according to the tables I've seen. All the pipe is 1" heavy wall PVC.

    The sytem has 1" Orbit Jar Top valves. These valve do NOT have as large an inside diameter (ID) as the 1" pipe. Thin or thick wall pipe matters not, the valves inlet and outlet ID are visibly smaller. This undersize ID at both the inlet and outlet must be creating an orifice and restricts flow. Stupid valve design.:nono:

    Question: What valve brand (if any) has a flow capacity (same ID and flow annulus) the same as the 1" pipe? I only need to replace 6 valves, so cost is not much of an issue.

    Thanks for loaning out your experience and expertise.
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,750

    You are much better off looking to modify zones to improve pressure and performance. For the record, a zone valve like an Orbit Watermaster is not very different than 'pro' one-inch zone valves.

    Messages: 18,668

    How many feet is the water traveling through that valve? A flow chart will give you the pressure loss and I doubt much will be gained by going to another 1" valve. This is not a defense of orbit just do the math before you put yourself through a useless effort.
  4. Steve P

    Steve P LawnSite Member
    Messages: 14

    I have 62 psig static pressure (no flow pressure) and the zone only has 4 Orbit Voyager II sprinklers. With size 8 nozzles in each sprinker, they are throwing 6 feet shorter than the Orbit table says they should. Each zone suffers pretty much the same lack of distance throw, so I don't think it's any one vave just not opening all the way.

    Seems anemic to me.

    Thanks for the advice.
  5. Sprinkus

    Sprinkus LawnSite Silver Member
    Messages: 2,322

    Simple answer

    Correct answer: What everyone else said or will say.
  6. S.O.Contracting

    S.O.Contracting LawnSite Member
    Messages: 186

    Put smaller nozzles in. The 8 is approx 4 gpm. Your system probably can't supply that volume regardless of pressure. Shoot for 12 gpm or so. Sounds like bad design from the start.
    Last edited: May 30, 2012
  7. Waterlogged

    Waterlogged LawnSite Senior Member
    from Texas
    Messages: 587

    How big is the meter? Is it open all the way ? Is there a master valve ? Are all gate valves open ? Read the meter when a zone is running how many GPM ? A #8 RainBird x 4 = 28 Hunter #8 red x 4 = 14.8 blue is more. I don't know about Orbit
  8. Steve P

    Steve P LawnSite Member
    Messages: 14

    1. 1"
    2. yes.
    3. Yes. 1" Ball Valve. 100% open.
    4. No gates.
    5. Good idea to check meter for actual gpm. I'll do it this weekend. thanks!
  9. Steve P

    Steve P LawnSite Member
    Messages: 14

    The Irritrol valve is exactly what I was looking for. But WOW! That's a pricey valve. Still, a choice to replace the Orbit junk and looks like a great valve.
  10. Steve P

    Steve P LawnSite Member
    Messages: 14

    I forgot to mention: this system has one of the prefab Orbit manifolds. It is the "old style" that they quit using in 2007 or 2008. The ID on it is also quit small. Actually looks like 3/4".

    I can make a 1" manifold and will likely try that first.

    I hate to think about a re-do on the whole system, but may have to be done.

    Again, thanks for all the replies.

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