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My theory on why TX is single valve versus manifold

Discussion in 'Irrigation' started by FIMCO-MEISTER, Apr 14, 2008.

  1. Since some seem bored with the 7 head battle I thought I would throw a theory out their and inflame the manifold folks. My point on the 7 head post is that manifold people and pipe pullers design their systems in which the heads are in a long series and downplay the psi difference between the first head in the series and the last. I was taught to find the midpoint and split the zone to minimize pressure differences between heads. Since installation methods (pulling vs trenching) (coming from the house vs street) and labor are such a big factor in irrigation installation we rationalize to justify what it takes to install a system profitably.

    This is not the point to this thread though. I think the tradition of TX irrigators installing single valves in the yard started in the days of copper systems. The cost of copper and labor involved sweating pipe mandated that systems be designed to minimize the larger copper sizes and allow for pipe downsizing as soon as possible. Combine this with our tie-ins always being at the curb. I'd like some manifold person to take an old design and redesign it using the TX method and do a material take off.
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,696

    No question that a minimum of pipe gets used in a proper mainline layout, but that doesn't relate to systems pulled with poly pipe, most of which may be "over-spec'd" to keep pressure variances to a minimum. I would do a curbside-meter install with a single manifold, and bump up the pipe size for the most distant zones.
  3. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    Fimco - this doesn't really answer your question, but one thing that hit me as I was reading your post, is with cold climate/poly guys we do have a shorter season than you warm/pvc guys. So finding a way to install faster is crucial. Our pulled poly systems, I believe, do go in faster than your pvc systems. Yes a little quality may be sacrificed sometimes by not center feeding and downsizing. But if we know what we're doing it has no affect on actual performance. I'm sure that not all pvc installs are done properly either.

    But with our 8-10 month season, we do need to install faster to make the money we want. Unfortunately this gives the get-in-get-out mentality. sorry I can't answer what you want, I will admit (again) that I do not have the education to crunch the numbers. I know how a system will go in here and work properly though.
  4. Dana you are saying exactly what I said. We rationalize our methods and measurements to our circumstances. Hydraulic perfection is an unreasonable cost.
  5. Tom Tom

    Tom Tom LawnSite Bronze Member
    Posts: 1,278

    Also, the size of our yards plays a role for the majority of systems out there.

    It can literally be 20' to the first head in a front yard and maybe 40' to the first head in a backyard from the valve manifold.

    But, like you said its more than likely the result of the intial point of connection- Texas right off the street and Colorado from the inside of home
  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,696

    Every now and then, some system reworking gets complicated, because the old poly pipe is not in the 'proper' place, going in a line from head A to B, and only then is it obvious that the original pipe was laid in trenches, and that the priority of the installation was to minimize the amount of trenching (by hand, probably) being done, even if more poly was used.
  7. AI Inc

    AI Inc LawnSite Fanatic
    Posts: 25,390

    Thats the answer right there, trenching.If I had to trench I would go single cans too.Also winterization , who cares if you cannot find the valve if you never have to. Systems that need to be winterized you need to find the valves anualy.
  8. Why do you need to find the valves? Can't you just turn them on to blow them out?
  9. AI Inc

    AI Inc LawnSite Fanatic
    Posts: 25,390

    With a rain dial you can blow out 3 at a time . With a pro c and RB valves ya can bounce back and forth keeping a few open at a time. By doing it thru the manifold you can blow out 4-6 zones at once. Also with int clocks you do not need access and dont have to scedule them.
  10. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    I'd say more than 90% of our controllers here are interior. And the H/O is not always home when we do the work.

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