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Thread: Micron creep

  1. #1
    Join Date
    Sep 2004
    Posts
    20

    Micron creep

    First time I've ever used a micron guage. 410a split system. I pulled vacuum and here are my results:
    Pump shut off at 144 microns.
    +1 hour: 275 microns (131 increase).
    +1 hour: 339 microns (62 increase).
    +1-3/4hour:413 microns (76 increase).
    So in 3-3/4 hours 269 micron increase.

    Is this amount of creep normal? Should this creep have stopped at some point?

    Also, I was thinking of leaving the vacuum pump on overnight but it's getting cold at night (34F low). What is too cold for leaving a pump on?

    Thanks and have a great day!

  2. #2
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Quote Originally Posted by nlovas View Post
    First time I've ever used a micron guage. 410a split system. I pulled vacuum and here are my results:
    Pump shut off at 144 microns.
    +1 hour: 275 microns (131 increase).
    +1 hour: 339 microns (62 increase).
    +1-3/4hour:413 microns (76 increase).
    So in 3-3/4 hours 269 micron increase.

    How much of this creep is from micro leaks? Is this amount of creep normal?

    Also, I was thinking of leaving the vacuum pump on overnight but it's getting cold at night (34F low). What is too cold for leaving a pump on?

    Thanks and have a great day!

    Sounds like a good vacuum and I applaud you for doing it right!!!


    Outside pressure differences, improper hoses and/or connections could be the reason for this creep. Internally you have a dry and clean system. Charge that sucker up.

  3. #3
    Join Date
    Dec 2007
    Location
    Ohio
    Posts
    2,875
    At 144 on your initial pull.....you're good....

    A small creep is fine....

    If you would have gone from, say, 144 to 500 in a matter of a few minutes,
    I would say you have a problem.....

    For a residential, split system, it shouldn't be necessary to leave a pump
    running over night...

    With the proper tools and set ups, a solid, 200 micron (or lower) vacuum
    can be pulled in 20 minutes....

    Great job using the micron gauge....glad to see more guys taking pride in
    their work!
    I need a new signature.....

  4. #4
    Join Date
    Sep 2004
    Posts
    20
    Thank you. You've given me important information I need to help me do a good job.

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