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Hydraulic Valves

Discussion in 'Irrigation' started by bicmudpuppy, Sep 27, 2005.

  1. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    Ok, just finished a hydraulic valve replacement, and something is bugging me. The valve I replaced was a pin type normally closed hydraulic valve. The hydraulic conversion kit I purchased instead of acquiring a new pin type, only had instructions for converting to a normally open hydraulic system. I see a minimum of 6 normally closed systems for each one normally open. Toro claims that the normally open hydraulic valve is/was the most common. What about what you guys are servicing? The repsonse list here will be short, but chip in if you can.
  2. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,799

    The response list will be very short :) I have not, and I doubt I ever will in this area, see a hydraulic system.

    I'd love it if you had a web page or something so I could better understand it.
  3. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    I'll get the camera out and take a picture, I saved the trash. :)

    The pricicpal is fairly straight forward. In normally closed systems, instead of solenoids and wires, you have one 1/8" id tube from each valve that goes back to the controller. The controller then operates a diverter valve that bleeds the tubes. I've even run the drain tubes into flower pots for customers. With normally open valves, the tubing provides the pressure to the top of the diaphram. Thus, you apply pressure to close the valve.
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,677

    Since there isn't any distance restriction between valves and controller on Normally Open hydraulic systems, I can see why Toro would favor them. You might leave the original (electric) valve diaphragm in the valve, and it might operate on the older pin-type controller, as long as it bleeds sufficient water. My Toro breakout book shows a specific pin-type-hydraulic diaphragm assembly (35-3655) for the one inch valve.

    I see mostly pin-type hydraulic Toro valves on the smaller systems, run by their little Freetime four-zone controllers. Larger systems would use Normally Open valves. Another advantage with the N.O. valves was their tolerance for dirty water, since there is nothing to get clogged up, since the upper chamber of the valve has no connection with the water it controls.
  5. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Almost ditto here. We pulled the last H.O. system out about 15 years ago. Used to have parts laying around but jettisoned them a few years back.

    Hayes :rolleyes:

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