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  1. #1
    Join Date
    Mar 2014
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    Trying to get down to 500 microns but stuck at 1200

    I left pump on for about 4 hours but when I went back o was stuck at 1250. I changed the oil but I haven't tried to vacuum again because it got to late. Will this solve my issue? I don't have a core removal tool do I need one? Ty

  2. #2
    Join Date
    Feb 2017
    Location
    New York
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    So many questions!

    What size pump, hoses, refrigerant and unit? How long was the unit open? Didn't pass a pressure test?

    Being stuck at 1200 usually means you still have moisture in the system depending on ambient temp.

    Leaving it in a deep vacuum will tell you what's going on. If it rises to about 2500 and levels out, it's moisture. I'd it keeps rising, it's a leak.

    And yes, core removal tool along with larger diameter hoses will decrease evacuation time.
    -----Stop, step back, relax and have another go at it.-----

  3. #3
    Join Date
    Mar 2014
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    Thread Starter

    3cfm, 5 ton goodman, yes it passed pressure

    Quote Originally Posted by BennyD View Post
    So many questions!

    What size pump, hoses, refrigerant and unit? How long was the unit open? Didn't pass a pressure test?

    Being stuck at 1200 usually means you still have moisture in the system depending on ambient temp.

    Leaving it in a deep vacuum will tell you what's going on. If it rises to about 2500 and levels out, it's moisture. I'd it keeps rising, it's a leak.

    And yes, core removal tool along with larger diameter hoses will decrease evacuation time.
    R22

  4. #4
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    Tell us about your pressure test particulars.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
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  5. #5
    Join Date
    Mar 2014
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    Thread Starter
    I charged with nitrogen to 150psi and let it sit for an hour. No drop in pressure and no leaks detected with leak detector

  6. #6
    Join Date
    Aug 2012
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    Change the pump oil, call the parts house and pay them to open up for some oil.

  7. #7
    Join Date
    Feb 2017
    Location
    New York
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    Did you isolate the pump and see what the pump itself pulls?
    -----Stop, step back, relax and have another go at it.-----

  8. #8
    Join Date
    Jun 2008
    Posts
    5
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    Double check your equipment.......lately I have had issues with almost-new hoses, Appion CRT's less than a year old, o-rings inside gauges, etc.....now I test to 20-50 microns all my gear before going at the pipes.....

  9. #9
    Join Date
    Sep 2014
    Location
    NH
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    Had a unit recently at a new construction hotel. Lines where roughed in over the winter, but didn't get to place equipment until this spring. We had to run about 15' of line through a wall and roof, we taped the ends of the line shut and had come back a week later to finishing the run after some more walls went up, then brazed the ends shut and pressure tested. Must have gotten some water in the lines during that week. Took over 36 hours and 3 oil changes on the vacuum before it would hold below 500 microns.

  10. #10
    Join Date
    Jul 2013
    Location
    Richmond, VA
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    Make sure you don't have oil in your micron gauge or hoses.

  11. #11
    Join Date
    Jun 2017
    Location
    Rockledge, Florida.
    Posts
    17
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    I echo the recommendations to double check your equipment. With R22 you will have mineral oil which has a much lower capacity for moisture than R134a/POE systems. I would only expect a moisture issue in this case if you had water actually get in the lines like fozziee said.

    Good luck!

  12. #12
    Join Date
    Mar 2014
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    Thread Starter
    I had oil in micron gauge. I also blew a ton of oil out of my gauge hoses. Thanks guys

  13. #13
    Join Date
    Jul 2017
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    I don't know about you guys but I test 22 systems to 300psig(410 to 450psig). In my experiences if I get to 800-1400 microns and the gauge just hunts in that area my gauge is dirty. If I climb slowly during the bounce test I start looking for a leak. If I get to 300 or so and see a slight increase then drop back to 300 while its pulling it's a leak. Crt's 1/2" hoses are a must. On most systems i will pull until my gauge reads 110 microns or less, then i start my bounce test(anything above 140 microns while pulling on my setup holds above 500)Hope this helps.

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