MP Rotators

Discussion in 'Irrigation' started by Frick, Jun 13, 2008.

  1. Frick

    Frick LawnSite Member
    Posts: 36

    I just swapped out my old brass heads for Hunter sprays with MP3000 heads. While the literature states 30 feet at 35psi, I realized that I probably wouldn't get that in real life conditions. What I wasn't expecting was only getting 15-16 feet radial distance. The heads are installed in a fenced in yard with a lot of trees in the neighborhood, so wind isn't a factor.

    Has anyone else had similar problems?

    I just realized as I was typing this the MPs have an adjustment screw on them. But don't they come set all the way open?
  2. Keen

    Keen LawnSite Member
    Posts: 50

    did you check your PSI?
  3. need more info on your system....psi, gpm available, number of heads on the zone, type and size of the control valve and the age of the control valve.
  4. Frick

    Frick LawnSite Member
    Posts: 36

    I'll get a PSI measurement as soon as I can, the system has a booster pump. There are 8 heads in the zone, the control valve is probably 30+ years old. The lines are 3/4"

    The MPs are in the back yard, the front yard has 5 pgps in the front, so I don't think gpm is a problem. What does concern me is the tree roots. When I turned the system on, I had very little pressure at any of the heads. After about 5 minutes I discovered a water bubble popping up. A tree root had pushed the line up and pulled a fitting apart. There had been a prior fix, but it went over the root and subsequent growth caused it to break again. I took some pictures, but I can't find the camera at the moment. I rerouted the line under the root, instead of over, and moved the T which had been sitting right on top of the root a couple of feet back.

    My fear is a root has damaged a line badly enough to hamper the flow, but not enough to cause it to break. Is that possible, the majority of the supply line is gray plastic, most of the system is 30+ years old.
  5. If your valve is 30 years old then the diaphragm could be worn out and no longer has the ability to flex thus it can no longer get full flow....
  6. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    A pressure test at the nozzles would be some good diagnostic information to have if trying to determine if roots are pinching a line.
  7. bobw

    bobw LawnSite Senior Member
    Posts: 807

    8 Mp3000's on a 3/4" line is not going to be very successful. Assuming they are at 180 (default setting for 90-270s, the most common), at 35 lbs, you're using 1.7 gpm per nozzle. 8 x1.7 = 13.6 gpm, much more than a 3/4 line will supply.

    Cap off a few heads and adjust your corner heads to 1/4 circle, etc and then try again with all 8. If you have already made the adjustments, and are still having problems, you may want to look at swapping a few 3000s for 2000s which use less than 1/2 the water per nozzle (of course, less coverage as well...)
  8. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 22,139

    What they said.....MPs work best around 45 psi, just like their big brother,
    the Toro Stream Rotor.
  9. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    Unless your trying to get maximum radius reduction.
  10. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 22,139

    How true, why fool around with that silly flow control?

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