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Sprinkler heads you can't find a substitute for

Discussion in 'Irrigation' started by Wet_Boots, May 22, 2006.

  1. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,267

    This is more a rap on the knuckles for past irrigation practices that failed to forsee the future, but back when, they didn't know there was anything wrong with what they were doing.

    Maxipaw/Minipaw heads, that are shooting well over 30 feet with 25 psi at the heads, on systems that can never have enough head pressure, regardless of gear-drive-rotor nozzle choice, to install a gear-drive in place of the impact heads.

    Older brass impact heads, with larger nozzles (like 3/16") that reach distances at low operating pressures that gear-drives won't match.

    Ditto for impact-heads that splashed water off to the side, and covered something important with that side-splash.

    Toro Super600s - some installs made every use of their distance capabilities, and when these things first hit the market, they had to appeal to folks that knew the brass impact heads they were using could absolutely cover a 40 foot radius. Think a Hunter PGP with a #4 nozzle can match a S600 PC1.3 for distance? Or any 1.5 gpm nozzle? Similarly with a S600 PC2.5, at certain pressures. Their higher trajectory was one reason, and the distance-over-uniformity nozzle design was another.

    Older PGPs, in some applications. I don't think Mr. Ed Hunter sold sprinklers with poor water distribution, even in the earliest days. But about ten years back the PGP nozzle designs were modified from the center-hole-plus-side-slot to the current rectangular hole, on sizes 5, 6, 7, and 8. A call to tech support got a response of "Yes, we know they don't give the same distance performance as they used to at lower pressures. But of course, you really want to have 50 psi at the heads anyway." (that's ever so comforting to hear, especially when the static pressure is barely 50 psi in the first place) ~ I think the modification has more to do with marketing, and competing with Rain Curtain nozzles, than anything else, unless clogging from debris was a factor. In any event, they should have left the original nozzle molds intact, so they could supply legacy applications.

    Various older high-trajectory rotors. I doubt that there are many still in use, but it was a real headache when it was obvious that some dead rotor was not replaceable with anything available, on account of the old rotor pitching the water up high with a 30 degree trajectory, and clearing some untouchable obstacle.

    Thompson rotor heads. If they still made them, they'd list for three hundred apiece. Anything from 4 gpm to golf-course-sized watering, depending on nozzles and stator selection. Another low-pressure-capable head you sometimes couldn't substitute for. Utterly unbreakable. By the way, if you look at the fixed-arc gear drives for a Toro 640 rotor, their angles are a match for the Thompsons.
  2. SprinklerGuy

    SprinklerGuy LawnSite Bronze Member
    Messages: 1,778

    Rain Jet spray heads that spray about 25 feet and are about 2 inches tall and the one piece brass nozzle/popup assembly that only pops up about 1 inch high....
  3. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,267

    Forgot all about Rain Jet. I saw one neighborhood that was riddled with systems that used their large-diameter low-gallonage model, along with undersized pipe runs, so a head at the end of the line could be spraying over 20 feet with less than 20 psi. I think that head ran on pressures as low as 15 psi. Full circles all over, spraying over curbs and into the street by an alarming distance.

    In general, it was mostly the lower pressures that made for headaches. There are few residential heads sold today that can reliably cover further in feet that their pressure in psi. I remember one old system pumping water from a creek, with heads running down the middle of an 80-foot-wide backyard, that covered it all with full-circle all-brass gear rotors pitching the water at a high trajectory, and nothing I had access to at the time (no Thompson) could duplicate the low-pressure coverage, and there wasn't any way to milk more pressure from the pump.

    I think someday I'll do a low-pressure system with a straight centrifugal (non-jet) pump and R-50s, and confound a future generation of repairmen. :p
  4. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    There comes a time when its cheaper to redo than repair....Except drip of course :laugh:.

    Up here, there aren't many systems that were older than the Hunter G-Type, so its not so bad. I typically replace a impact with a rotor if I have to, but at least you can still get Maxipaws.
  5. NC_Irrigator

    NC_Irrigator LawnSite Bronze Member
    from NC
    Messages: 1,444

    TORO 300 stream rotors are a hard match
  6. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    Yeah, but they still make those :)

    As much as I hate them, I'll replace a failed 300 with another one.
  7. Ground Master

    Ground Master LawnSite Senior Member
    Messages: 505

    older weathermatic brass spray heads with the 20' nozzle
  8. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    I was thinking the same thing.

    Too much trouble aligning the arc disc? Or do they use the adjustable ones up there (XP?) that are a real PITA. I'll stick with the originals. :laugh:
  9. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    Seems that newer pop-ups with 17' nozzles would integrate fairly nicely. :)
  10. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    The arc discs are easy to align. Its just that the damn things stop rotating.

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