11 zones in one manifold or 6/5 in two

Discussion in 'Homeowner Assistance Forum' started by hadfield43, Jul 30, 2013.

  1. hadfield43

    hadfield43 LawnSite Member
    from wyoming
    Posts: 50

    Thank you for the links - I will test out of the backflow (which I installed already)

    I did run another test from a faucet near by and got this time only 7 GPM :(

    I did a different test previously showing 9 GPM

    Both were with all the water off in the house.
     
  2. hadfield43

    hadfield43 LawnSite Member
    from wyoming
    Posts: 50

    Well I think I am going to take your advice, with just a little tweaking - may as well move that one on the East Side a bit more in toward the grass or at least in the rock bed area.

    The irony is the place where I originally thought to have my manifold is where there is the least need for Valves, this is just because the copper was there and I had my blinders on that the manifold needs to be near to the copper.

    Will run 1.5" lines to each one.

    Will look at the math stuff tonight.

    Capture.jpg
     
  3. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    You need to crunch the numbers before you choose a line size for the main. I also would recommend not running the main through a manifold, instead tee off the main, and keep the manifolds out of the grass.
     
  4. hadfield43

    hadfield43 LawnSite Member
    from wyoming
    Posts: 50

    Okay, here is my calcs.

    Now I did 3 tests yesterday on my Gallons Per Minute - they all hovered around 7.

    Previously when I had measured this it was about 9.

    I just did this with the faucet fully open, this is a faucet about 10 feet from where my copper comes out and backflow is installed.

    The first file assumes I get a lack luster 7GPM

    I also put the chart for the sprinkler heads I was planning to use on there

    7GPM CALCS.jpg
     
  5. hadfield43

    hadfield43 LawnSite Member
    from wyoming
    Posts: 50

    Here are the calcs at 9GPM - I don't think this matters, as I am pretty sure I am getting 7-7.5

    9GPM CALCS.jpg
     
  6. hadfield43

    hadfield43 LawnSite Member
    from wyoming
    Posts: 50

    Here are my concerns:

    1) I am pretty sure after the main line in my house is 3/4" copper, that's certainly what they installed out of the wall and is all around in the utility closet.

    2) I am worried that I got different GPM readings, each time I check there is no water running in the house.

    3) According to the Toro chart for the 32SA (ASSUMING my pressure is 55 - I think they mean dynamic) - I need between 1.7 and 2.2 GPM (I assume that means per head) to get 26 feet (this is how I flagged and planned each zone)

    My life would be made easy if I could keep my 26ft to 26ft head-to-head plan, with up to 4 heads per zone. BUT If I am only getting 7-7.5 GPM doesn't this mean it wont work if I need say 2GPM x 4 heads (8GPM)?

    Here are my questions:

    1) Does the number crunching look right (assuming I have the distance and pipe types/sizes right)?
    2) Should I plan on only having 3 heads per zone?
    3) What do you think of me physically testing and seeing as I had with 3/4" poly previously, but now with 1" or 1.5" PVC, etc.
    4) Looks like 1" PVC is fine, don't you agree?
     
  7. hadfield43

    hadfield43 LawnSite Member
    from wyoming
    Posts: 50

    Kiril - assuming you answer these questions (thank you in advance) - or thank you in advance to anyone else that responds.
     
  8. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    You need to find out what you meter size is and the line size coming out of the meter. Ideally your POC would be as close to the meter as possible.

    Also you need to test flow and pressure at different times of the day .... the most important time would be during the normal run time of the irrigation system (ex. 3 AM - 9 AM).

    Also curious how you are determining your dynamic PSI and flow rate?

    Using MPRotators will allow you to put more heads per zone as their flow rates are relatively low.

    http://www.hunterindustries.com/irrigation-product/nozzles/mp-rotator

    I can't speak on what they appropriate mainline size should be. It depends on pressure, maximum flow and length of the line. Use the charts to determine what is the best size to use.
     
  9. hadfield43

    hadfield43 LawnSite Member
    from wyoming
    Posts: 50

    Kiril, Thanks again for all the help - you have been a massive help. I got lucky and found a friend that has done many professional installations, was able to take your advice + his and finish the plan.

    The one bit of good news is that I got 11GPM at the backflow vs. the hose bib at 7GPM.

    The one contradiction he had with you is that with these colder climates he wasn't as big on having so much pressurized PVC and limited the manifold boxes back down to 3. I am sure this is just a preference thing, but he said sometimes youre just better off spending just a little extra on poly runs than have a mess.
     
  10. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    Put a master valve in. I would do that by default anyhow given the property size. :)
     

Share This Page