nozzle gallonage

Discussion in 'Irrigation / Sprinkler Forum' started by teamo, Jul 4, 2010.

  1. teamo

    teamo New Member

    Messages:
    95
    Location:
    Massachusetts
    I have Hunter rotary heads. I installed the system myself about 5 years ago. One of the things that I have always questioned about my nozzle selection was the gallonage output on each individual head. At the time that I set them up I installed 2 gpm nozzles on the heads that do a full circle and for 3/4th circle patterns I used 1.5 gpm nozzles. On the sides along walkways I used 1 gpm, in the corners I used .05 gpm nozzles. I had read that the reason for doing this is because you are only using half of the area for a half circle so only one half the gallonage is needed, the corners are only one quarter, etc. I have noticed that I having some brown patches at some parts of the yard. I know this could be due to lots of variables such as bugs, grubs, soil type, etc, but should I increase the gallonage on some of the lower output heads? Do most people use different gallonage nozzles for different areas or the same for every head in a zone? I did a calculation when I was designing the system and I have about 15 gpm available. I put 5 or 6 heads per zone so even @ 2gpm output per head/per zone I would still have 3 gpm residual leftover.
  2. Fireguy97

    Fireguy97 Irrigation Contractor

    Most people (who install systems themselves) use the same nozzle for everything. You have done it the proper way. You always want to balance the GPM vs the time of operation. If all of the mentioned heads are on the same zone and are running at the same time over the same type of turf then everything should work.

    If you bump everything up to 2 GPM, then you will be putting out less water over the same time at the 360's.

    Are the brown spots under the spray of water, or near an edge of the spray? Do your heads give head to head coverage? Just to verify your output place a bunch of empty tuna cans out on your lawn (brown spots and green spots). You will visually be able to see the water that is on the turf. Turf will be very happy with 1" water per week.

    Mick
  3. teamo

    teamo New Member

    Messages:
    95
    Location:
    Massachusetts
    Thanks Mick,
    I think that I have pretty good head to head coverage. I used good overlap from head to head. I think that I will have to try the cans out there as you suggested and measure what I am actually getting for water and see if I need to adjust the time for each zone.
  4. dargo

    dargo New Member

    Messages:
    36
    Location:
    MA
    how do you know you are getting the GPM per head? Do you know the static PSI per head? You did an avg calc but the first head on a line will get more PSI then the last.
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