What is this valve, also MP rotator Q

Discussion in 'Irrigation' started by nacarson, May 12, 2008.

  1. nacarson

    nacarson LawnSite Member
    Posts: 15


    I learned a terrific amount from this forum (Peter, Kiril, Mike, Rotor, everyone else) and installed my own homeowner system last year. All is running well after 1 year, no problems, no dry spots and less water usage than neighbours!

    Anyhow I want to help out one of my neighbours. He has a larger lot. 40+yr galv 1" supply line, with 3/4" mainline and 60ft laterals with 8+ sprays on each, pushing 14gpm+. Used to work, now on some zones the heads don't even pop up fully. Probably the line rusting etc. I used 1.25" main/1" lateral for an even smaller configuration.

    So I plan to put in MP rotators to avoid too much digging. My design cuts the number of heads by over half, and the gpm on the zones by 2/3, and gets rid of some mid-lawn spray zones completely.

    My question for the pro's surrounds this valve (pic here). I'm sure you are all familiar with it:


    1) What's the pressure loss in this thing - is it worth cutting out and replacing with an ASVF? It sounds like water is gurgling its merry way through when zones are running, but it doesn't feel like there's a lot shifting through it.

    2) Also is it possible to open/close the valve manually without using the timer? It doesn't have a big friendly knob on top like the ones I installed ;)

    Thank you all,


  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,697

    How many zones? Are there any other valves like this one?
  3. irrig8r

    irrig8r LawnSite Platinum Member
    Posts: 4,535

    That's a manual bleed screw (slotted, and knurled around the edge) at the bottom of your photo. A quarter turn or so counterclockwise with a flat blade screwdriver will open the valve.

    Be aware that on an older one of these valves that the 0-ring under that bleed screw might be cracked or worn flat, and that you might have a hard time preventing a trickle leak from it if it's been used a lot.

    The center screw is the flow control.

    And you might find this useful.

  4. nacarson

    nacarson LawnSite Member
    Posts: 15

    Boots - yes, there are another 7 valves manifolded. Two of those should be out of action with MP rotators instead.

    Gregg- thanks for the link. I'll call you guys out if I screw it up :) (palo alto)

    The valves are most likely 20-30 years old, so given your advice I'll stay away from the bleed screw. Probably the rubber may crack as soon as it's turned.

    I also notice they have a 'flow adjustment' capability. I wonder why anyone would want a zone to run at anything but full pressure, and perhaps this could also be a factor in the the reduced pressure. Maybe a way of reducing the throw of all nozzles on the zone at the same time?

  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,697

    You can get more flow-efficient antisyphon valves than the Champion you pictured. Ideal would be an Irritrol 2713APR, because you can swap the solenoids from the Champions.
  6. nacarson

    nacarson LawnSite Member
    Posts: 15

    Thanks 'boots. At say 3/4" valve running 8gpm how many PSI loss are we talking about for both anti-syphon valves? My static pressure is ~42psi, but I have no idea just how much flow these very old champions are restricting.
  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,697

    Your flow will determine the pressure gain. Maybe 5 psi. It's worth the money to switch.
  8. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 21,976

    The flow control is double faceted: it does, indeed allow you to fine tune the
    sprinklers should you have some overspray, It is also used to seat the valve diaphragm for proper closure. The technique is to turn the flow control down
    until a drop in application is noticed, then turn the flow control up a quarter
    turn or so & the diaphragm is adjusted. DO NOT use the flow control as a
    shut-off or you will be calling Gregg. :nono:
  9. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    Agreed, except the part about the solenoids. Curious why the pressure all of a sudden became an issue? Did you locate the cause?

    If pressure is an issue, you might consider upsizing to 1" valves as their Cv (flow coefficient) is much better than 3/4".
  10. irrig8r

    irrig8r LawnSite Platinum Member
    Posts: 4,535

    Yeah, Boots, what do you mean about swapping the solenoids?

    Those are the same as found on Superior, not Richdel-Hardie-Hydro Rain-Irritrol-LawnGenie-RainJet...

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