Pressure Regulator For Blowouts

Discussion in 'Irrigation' started by White Gardens, Oct 10, 2012.

  1. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    First off, thanks for all the input on my question(s).

    So the compressor I rented is a Sulair 185. The rental house informed me to watch the pressure gauge so that the pressure doesn't drop below 100psi on the gauge attached to the unit.

    They were told by Sulair that if it does, then the oil separator for the screw pump won't separate out all the oil and potentially I could blow oil into the irrigation systems.

    So, I rigged up my own pressure gauge. I couldn't find one that I liked that had a bigger opening to not restrict CFM's during a blow out. I've got a bigger 9 zone system that I need to do tomorrow and the access cap in the line is 1.5".

    Here's the pic, and I'm also disappointed in the installer for not putting in a better blow-out valve. I ended up having to remove a test port and use an 1/8th inch adapter to get it connected.

    The gauge worked great and never cracked the valve enough to go past 75psi. The machine kept a constant 120 psi on it's gauge.

    Even with the 1/8" fitting, I still felt I was getting sufficient air flow through the system.

    I also used a zip tie to hold the hose in place to make sure not to break the fitting.

    Thanks again. :waving:



  2. Mike Leary

    Mike Leary LawnSite Fanatic
    Messages: 23,174

    Nice pic, well done! A lot of smaller systems will not like 100psi. :nono:
  3. cjohn2000

    cjohn2000 LawnSite Senior Member
    Messages: 570

    Cool that looks like our old setup. The new setup I built has a ball valve, pressure gauge, gatevalve, pressure gauge. The idea is to use the gate valve to better regulate the air, globe would be better but more pricey. Why remove the testcock? We usually just screw into it and open it. BTW two 1/4" street 90s help reduce stress on test cocks at least for the backflows in the ground:waving:
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,759

    With a 3/4-inch or 1-inch supply line, you probably can't fail to get enough air through the RPZ connection.

    Better to have a small "whip" hose to connect to the testcocks.
  5. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    Ya, I was concerned that the ball valve in the RPZ connection was too small to efficiently allow air to flow through, I was just trying to ensure proper air flow. Good to know that just hooking into the testcock will be sufficient.

    As for the design on the gauge, this is what I basically came up with in a pinch. Now knowing hat I need to do, I plan on building a better pressure gauge next year, so thanks for the design advice.

    I rented the compressor for the weekend to give myself ample time to get the 5 blowouts done that I need to do

    Here's a question for you guys.

    When blowing out a zone, when do you think it's sufficiently blown out? The one I did today, it seemed like I would get one head out six that might be spiting water, but the rest were dry.

    I played it by ear, and just figured enough was enough and shut down that zone and went to the next. After I ran through, I hit each zone one more time and I would push a bit more water out until one or twos head might have a light mist and no real spurts of water.

    I wanted to go until there was no water coming out at all, but I was afraid of pushing too much air through the dry sections and melting parts of the system.


  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,759

    When the furthest head of a zone is fully popped up and blowing air, you are done.
  7. cjohn2000

    cjohn2000 LawnSite Senior Member
    Messages: 570

    On one of our older complexs that has the old 2" doublechecks with needle valve testcocks and gate type isolation valves, we blow out through #4 testcock and on that one you can see that there is some air restriction going through such a small opening.

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