Design Question?

Discussion in 'Irrigation' started by Broker, Mar 25, 2005.

  1. Broker

    Broker LawnSite Senior Member
    Messages: 382

    When designing a system do you all stick with MPR's with your rotors? And do your crews follow through with the different nozzles for different head locations or do you just stick with the same numbered nozzles.
  2. Rotor-Man

    Rotor-Man LawnSite Member
    Messages: 126

    Love to read about matched prec. rates, and how it is preached in design classes, but in reality on the repair jobs I've done their are not many yards that have MPR. On new installs I do, I always try to use MPR. I think the customer in the end just loves to see more water coming out of the rotor, and is pretty much clueless on MPR. JMHO.
  3. Ground Master

    Ground Master LawnSite Senior Member
    Messages: 505

    To truly match your precipitation rates on a rotor zone you have to measure the distance each rotor will throw and the arc that rotor covers(90, 120, 180 degrees, etc.)

    With those numbers you can calculate the area each rotor will cover.


    rotor 1 is set to throw 20' and cover 90 degrees(1/4 of a circle)= 314 square feet covered

    rotor 2 is set to throw 20' and cover 120 degrees(1/3 of a circle)=418 square feet covered.

    rotor 3 is set to throw 24' and cover 180 degrees (1/2 of a circle)=905 square feet.

    so if you use a 1.5gpm nozzle on rotor 1,
    you'll need a 2.0gpm on rotor 2 and a 4.3 gpm on rotor 3

    but of course you won't find these exact nozzles so you'll have to use the closest match.
  4. Broker

    Broker LawnSite Senior Member
    Messages: 382

    Rotorman: I hear yeah. I never see mpr on service calls so I am starting to push system audits to generate more service and to show the homeowner that we can make their systems more efficient since water and sewer rates are on the rise.

    Groundmaster: I know how to design with mpr. I was asking if people follow through with it in design and installations.
  5. MikeK

    MikeK LawnSite Member
    Messages: 145

    Every system we instal is nozzled as close as possible to MPR.
    We will never install different heads on the same zone, I will not even install a Mini rotor on a zone with Large rotors.
    In addition, we are now giving each customer a sheet where we caculate precip rates for each zone and tell them how long to run each zone to apply a certian amount of water.
    We use these in our sales presentation and try to set ourselves apart from the other contractors.

    In the end, it saves the customer water and that's something that we all should be working on. to manage our finite resources.
  6. Broker

    Broker LawnSite Senior Member
    Messages: 382

    MikeK your are doing it right
  7. advancedlawnsolutions

    advancedlawnsolutions LawnSite Member
    Messages: 62

    Its good to here that others out there are attempting a "professional" install or repair. I also try to use MPR's and never mix match heads on zones. But it's amazing to me what some folks are doing. Like sprays with rotors on a zone. I see that a lot. How about head to head coverage? I know design schools will teach to put head to head and I do for the most part but occasionaly depending on the lay out its hard to do.
  8. Broker

    Broker LawnSite Senior Member
    Messages: 382

    I think that seeing rotors and sprays on the same zone would be more common on systems 5 years and older but anyone that took a design course would think the same thing that it is irresponsible of a "contractor" to do that.
    As for spacing of rotors we never exceed 30-32' for spacing a PGP rotor with the following conditions as an example 2-4gpm @ 50+ operating psi. Some companies will space in the 40' range and have no problems but we never exceed 32. So we guarantee head to head coverage. A lot of the landscapers we work are happy we space this way. I definitely agree that it is amazing what we see on service calls. Once the season starts I am thinking about showing bad service call pics and some install pics.
  9. advancedlawnsolutions

    advancedlawnsolutions LawnSite Member
    Messages: 62

    After these last 2 jobs I did on an existing system, I learned that it is worth it to charge a little more for having to come in behind somone else. I spent most of my time trying to figure out what was going on than I did on the actual repairs. There were broken sprays all over and by the time I fixed it and turned the zone on I found some new heads from the increased pressure. --Lot of fun. Charge more for clay soils also.
  10. jerryrwm

    jerryrwm LawnSite Bronze Member
    Messages: 1,274

    Not sure I understand this statement. There have been knot-heads installing sprays and rotors since they have been installing sprinkler systems. And they are still doing it today.

    Attendance at a design course, successful completion of a state licensing exam, or the IA exam does not guarantee a good system. It does not mean that the contractor, "irresponsible as they may be", will really care what kind of system goes in. Their reasoning is that the homeowner really only wants a system that waters his property. So what if there is water on the driveway, on the sidewalks, on the fence, on the house, etc. After all, those things got wet when he did it with his hose-end sprinkler. What he is concerned with is that now he's not wasting water because he forgets to turn off the hose.

    So if there are rotors on the spray zone, the heads spray across the front walk, and the beds are all watered from the front and water blasting the house, so what. The homeowner has a sprinkler system and that's what they thought they wanted.

    Until there is a complaint filed with an agency that has the authority for action, and has the laws in place to act as a guide, and an agency that actually does the policing of the industry, you are going to have those "irresponsible" clowns out there. You just have to sell the benefits and features of your particular style of irrigation and don't worry about the other ones. You build up the clientel based on your merits and don't bad-mouth the competition and their tactics. Bad-mouthing can bite you in the ass - you never know if their father/brother/etc. had a system installed by Jake-Leg Irrigation and they are happy as hell about it.

    Why not bid everything as if there was clay soil, and then you make more money when in the sandy soil? That way when two friends get to talking about the sprinkler systems you just installed for each of them, one doesn't get pissed because you charged him $600 more for essentially an equal system - # of zones, # heads etc. Just a thought.

    Jerry R
    TLI #1452

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