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  1. #1
    Join Date
    May 2018
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    vacuum pump issues

    The last two days we've been installing residential A/C's and have had issues on both so i'm trying to figure out if it's equipment or installation issues. The problem is the numbers on the micron gauge fluctuate or bounce 970 down to 960 then back up to 970) and stay there for quite awhile before the set of numbers starts to lower as it continues to bounce. now today on a different system but same pump and micron gauge it's pulling extremely slow going on 2.5 hours now and down to 762. we've already changed the oil in the pump. now what?

  2. #2
    Join Date
    Feb 2017
    Location
    New York
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    What does you pump pull down to all by itself? Are you pulling through a manifold?
    Sounds like moisture to me.

    Sent from my SM-G920V using Tapatalk
    -----Stop, step back, relax and have another go at it.-----

  3. #3
    Join Date
    May 2018
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    Thread Starter
    yes we are pulling through a manifold. haven't tried to see how far it will go down but if we close the manifold on both sides it drops fast and we stopped doing that when it was below 500. I'm not sure if it makes a difference but the micron gauge is built into my fieldpiece manifold set

  4. #4
    Join Date
    Feb 2017
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    New York
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    That point will be lower than the pressure in the system. If you valve off the pump, you'll probably see it rise to 1500-2000 microns. I'm guessing the ambient temperature is in the 70's. That is moisture.
    Good job continuing the evacuation! Most would call it good.

    Sent from my SM-G920V using Tapatalk
    -----Stop, step back, relax and have another go at it.-----

  5. #5
    Join Date
    May 2018
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    Thread Starter
    Thanks BennyD for the insight I'm going to pull a vacuum on a cylinder at the shop later tonight and see if there's any issues.

  6. #6
    Join Date
    Jun 2014
    Location
    Dover, DE
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    Get rid of the manifold and straight pipe it with core removers. You’ll be amazed how much faster things get.
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

  7. #7
    Join Date
    Feb 2017
    Location
    New York
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    Quote Originally Posted by rider77 View Post
    Get rid of the manifold and straight pipe it with core removers. Youll be amazed how much faster things get.
    Yes! It does make a world of difference! Even if you only have " connections, bigger is better. You could hook up your manifold to the side port on the core tool to use the micron gague if you don't have a dedicated micron gague.

    Sent from my SM-G920V using Tapatalk
    -----Stop, step back, relax and have another go at it.-----

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