Vacuum setup - Page 2
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Thread: Vacuum setup

  1. #14
    Join Date
    Feb 2010
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    In a boiler room
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    Quote Originally Posted by pacnw View Post
    Try explaining this to mfrs, Lennox, that do not allow the use of CRTs on most resi equip!!!! http://hvac-talk.com/vbb/images/smilies/gah.gif
    We are a lennox dealer, and I haven't heard this. What is their reasoning?

  2. #15
    Join Date
    Dec 2007
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    4,663
    I meant that they are manufactured so that cannot get the CRT on one or both service valves.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  3. #16
    Join Date
    Mar 2011
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    East Coast FL
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    You can also evacuate without a core removal tool.

    - pull schraders
    - evacuate
    - when evacuation is complete , open liquid service valve and allow pressure to reach 5 to 10 lbs on low side , then re-close liquid valve
    - if package unit or system void of refrigerant then add charge to reach the 5 to 10 lbs then stop
    - remove hose , place thumb over port and then quickly install schrader
    - little refrigerant is lost

    Just another option

  4. #17
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    Quote Originally Posted by pacnw View Post
    I meant that they are manufactured so that cannot get the CRT on one or both service valves.
    Ahh yes, now I see what you mean.

  5. #18
    Join Date
    Nov 2007
    Location
    Mississippi
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    1,238
    I like to have my micron gauge as far away from vac pump as possible. Also, I leave the cores in. My core removal tool works great on core replacement of a "pressurized system". I would not trust that it is tight enough to pull vacuum through.

  6. #19
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    Nov 2010
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    Quote Originally Posted by socotech View Post
    I like to have my micron gauge as far away from vac pump as possible. Also, I leave the cores in. My core removal tool works great on core replacement of a "pressurized system". I would not trust that it is tight enough to pull vacuum through.
    Aside from adding a service port somewhere on the system, right off the CRT is as good as it gets. Heck I suppose a guy could try put the gauge at one service port and hoses on the other?

    Brainstorming... Is there a way to test the vacuum capability of a CRT? Putting my vacuum hoses on one CRT and a coupler at the female end of CRT with my gauge on it? When it pulls down I can blank off my pump, see what it holds.
    "I've got my Gas Mechanics license"
    "Yea, well my 16yr old daughter has her drivers license, doesn't mean she knows how to drive"

  7. #20
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    Dec 2011
    Location
    San Antonio, TX
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    Where and how are you blanking off?

    Sent from my ADR6350 using Tapatalk 2

  8. #21
    Join Date
    Nov 2010
    Location
    N. Idaho
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    The JB pump has an isolation valve right on it, turn the knob 45* and it's blanked off.
    "I've got my Gas Mechanics license"
    "Yea, well my 16yr old daughter has her drivers license, doesn't mean she knows how to drive"

  9. #22
    Join Date
    Apr 2012
    Location
    Chicago, IL
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    Lots of good ideas with this thread, and lots of things I'd like to try. To be honest, I usually just evacuate right through my gauges and right through the cores though, just because I'm in a hurry and also when I know the system should be fairly good (i.e. little or no exposure, same day service, no burnout, etc.)

  10. #23
    Join Date
    May 2010
    Location
    Tennessee
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    359
    Here is my question. When you go to put the schraders back into the service ports using the VCRT how do you keep that small amount of air from entering the sytem?

  11. #24
    Join Date
    May 2004
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    1,832
    Quote Originally Posted by JTCHVAC View Post
    Here is my question. When you go to put the schraders back into the service ports using the VCRT how do you keep that small amount of air from entering the sytem?
    Charge the system first.

  12. #25
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    May 2010
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    Tennessee
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    Quote Originally Posted by 270wsm View Post
    Charge the system first.
    Facepalm

  13. #26
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    May 2010
    Location
    Tennessee
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    Here is my setup
    Attached Images Attached Images     

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