Discussion in 'Irrigation' started by Mikol, Feb 25, 2005.

  1. Mikol

    Mikol LawnSite Member
    Messages: 51

    Can anyone help me? I have a 5/8 water meter and a 3/4 line to the house. can anyone maybe give an idea around how many sprayers and rotors I can use on a zone.I plan on using rain bird 1800 4" pop up and Hunter I-20 rotors.also I had a static pressure of 60. :help:
  2. Ground Master

    Ground Master LawnSite Senior Member
    Messages: 505

    10 gallons per minute
  3. aquamtic

    aquamtic LawnSite Senior Member
    Messages: 303

    At 60 psi- about 8gpm. You should design to 80% of that to be safe which is around 6gpm.

    On the sprays it all depends what distance nozzles you are using to determine the gpm required on each.

    As for 1-20's be careful they require sufficient gpm and dynamic pressure. Again these also depend on your distance you are trying to get. I would say no more than 3-4 heads with a#3

    PGPS are more flexible with lower pressure and gpm.
  4. Mikol

    Mikol LawnSite Member
    Messages: 51

    First of all Thanks to Ground Master and Aquamtic for the responses.Aquamtic I plan on using #10 spray nozzles on my Rain Bird 1800 serious 4".can you give me a rough idea on how many heads I can put on a zone .once again Thanks .
  5. aquamtic

    aquamtic LawnSite Senior Member
    Messages: 303

    What radius are you doing. Half, Quarter, Full Circle.

    and what model nozzle
  6. Mikol

    Mikol LawnSite Member
    Messages: 51

    Half,sorry about that
  7. aquamtic

    aquamtic LawnSite Senior Member
    Messages: 303

    If you use the MPR 10' Model, up to 7 on 1800's

    If you use the VAN series, up to 4

    If your doing standard half circles, go with the MPR, much nicer spray and less GPM
  8. jerryrwm

    jerryrwm LawnSite Bronze Member
    Messages: 1,274

    How far from the meter to the house? Also, what size and how long is the service line from the city main to the meter? Is the mainline on your side of the street or across the street? If across the street figure approx 40' of service line. On your side figure approx 10' for pressure loss calculations. You will lose about 2.0 psi if the main is on your side, and about 8.0 if across the street.

    If you replaced the supply with 1" or tap in directly behind the meter, you could safely get 10 - 12 gpm from that 5/8" meter with a 5.1 psi pressure loss through meter. Starting with 60 psi static and adjusting 10% for fitting loss etc, and deducting loss in service ( using 2.0 psi for this scenario because it is an unknown) you will have about 47.0 psi left to work with on the downstream side of the meter. Allowing 4.0 - 5.0 loss through a PVB or DCA (higher for a RPZ) you are at about 42.0 - 43.0 left to work with. Allowing about 2.0 psi loss through the valve, you have about 40.0 psi left. Assume a under head pressure of 30.0 psi, you will be able to size the lateral piping and mainline piping to lose no more than 5.0 each.

    Using a #3 nozzle on the I-20 Ultra at 35.0 psi, you will be flowing approx 2.2 gpm per head with a non-adjusted radius of 35'. Head spacing should be around 30', and you should get a precip rate of about .47 in/hr. if they are all half circle heads.

    PR (in/hr) = (2.2 GPM x 34560) / 180 deg x 30 ft x 30ft

    So, having said all that, you can probably run 5 of the I-20 heads per zone - provided you can increase the service line, and there are no significant elevation changes.

    Hope this helps,

    Jerry R

    Question to Aquamtic - do you actually put in a lot of 4.0 - 5.0 GPM zones? That adds up to some pretty large controllers and a long watering window, especially on a 1/4 acre and larger lot. I understand that the meters and BFD may be inside the basement, but a 3/4" Sch 40 service line at 9.0 gpm is going to have a pressure loss of 6.4 psi/100' and a velocity of 5.4 fps. Which would be a zone that is twice as large. Resulting in fewer zones, smaller controller, and a narrower watering window. Not questioning per se, just curious.
  9. YardPro

    YardPro LawnSite Gold Member
    Messages: 3,570

    hire a professional.
  10. Mikol

    Mikol LawnSite Member
    Messages: 51

    Can anyone tell roughly around how many sprays heads on one zone with Rain Bird 4" pop up #10 nozzles (halves)1800 serious. and always Thanks to all the replies.I guess by now everyone knows that I am a rookie. :dizzy:

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