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Thread: SIGHT GLASS

  1. #1
    Join Date
    Oct 2011
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    Cicero, IN.
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    47

    SIGHT GLASS

    I have several Carlyle O6D compressors and the oil level sight glasses have become clouded over and checking the level seems impossible. Is this a sign of a previous burnout? Running for extended periods of time with low oil level? Can these glasses be saved by cleaning or do I need to order replacements? Thank You Kirk

  2. #2
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    Western PA
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  3. #3
    Join Date
    Jul 2011
    Location
    Atlanta
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    Site Glass Clouding Issue

    Yes you can clean crankcase sight glasses. They should not get dirty but can become clouded or etched due to a previous burnout or an incomplete refrigerant oil changeout. Test the refrigerant and oil for any acid content. If the refirgerant has been changed you can get an oil test kit which can identify too much residual oil.

  4. #4
    Join Date
    Oct 2011
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    Cicero, IN.
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    Could a guy get away with cleaning glass, changing oil, and just purging air from compressor? Or is a complete evacuation called for?

  5. #5
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
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    11,296
    Proper procedure is to evacuate anytime after the refrigerant circuit is opened, which would include the compressor sump.

    If the sight glass is etched, you will have opened up the sump for naught. Get a new glass before you begin and you'll have 100% confidence that when you're done, the glass is clear.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  6. #6
    Join Date
    Jul 2011
    Location
    Atlanta
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    2
    I would isolate the compressor and reclaim the gas. Test the oil for acid or contamination from oil mixes. Kits are off the shelf at most supply houses. Attempt to clean the sight glass, change if needed. Change the oil if needed and pull a vacuum on the compressor. Open valves and put the unit back in service.

  7. #7
    Join Date
    Jan 2004
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    Lancaster PA
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    67,763
    Moved to Tech to Tech Commercial forum.
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    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  8. #8
    Join Date
    Dec 2005
    Posts
    1,908
    Quote Originally Posted by kaptnkirk View Post
    I have several Carlyle O6D compressors and the oil level sight glasses have become clouded over and checking the level seems impossible. Is this a sign of a previous burnout? Running for extended periods of time with low oil level? Can these glasses be saved by cleaning or do I need to order replacements? Thank You Kirk
    It ain't easy to take out. Take a chance to tab it off. Or buy a tool to open these glasses. I once tandem two of these together and it is a bitach

  9. #9
    Join Date
    Apr 2012
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    Paper Street Soap Company
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    2,304
    Shut the suction king valve while the compressor is running with gauges attached allowing it to shut off on low suction cut out. Immediately close off discharge king valve AFTER killing power to the unit.

    You wont have much left in the way of refrigerant.

    Acquire a tool to remove the sight glass. While you're at it take a oil sample and check for acid content. If acidic follow correct clean up procures to do a full clean up.

  10. #10
    Join Date
    Oct 2011
    Location
    Cicero, IN.
    Posts
    47
    I have always been puzzled a little. I had a boss in Texas 30 yrs ago ask me what was taking me so long changing a TXV on a coffin case in a grocery store. Condensing units on the roof. I said I was in the process of Evacuating the system. He said why would I do that? He said refrigerant is heavier than air and no air could enter the system. Thus no evacuation needed. I have always evacuated systems after opening to the atmosphere. I no longer carry a vacumn pump and I am just a troubleshooter/ electrical fixer and sub out all refrigerant repairs. I was just curious as to wether a guy could pump out sump, drain oil, clean or replace glass, pump in fresh oil, and purge sump. Thanks I am eager to hear your responses.

  11. #11
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,296
    Purging does not displace moisture. And if you're working with POE oils, you're dealing with an oil that is VERY hygroscopic (meaning it absorbs moisture ridiculously easily). Evacuation and fresh liquid line driers are your best defenses against moisture and contaminants.

    Worrying about air only is merely addressing a non-condensible problem...even there air contains moisture.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  12. #12
    Join Date
    Jul 2012
    Location
    Western KY
    Posts
    1,221
    Years ago this was fairly common. Valve out pull down to 3-5 psi make repair quickly and open valves. Thought being with some positive pressure pushin out nuttin could get in. Not acceptable practice since 92 but still done I'm sure.

  13. #13
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    Pull a plug out of a crankcase full of oil with even 1psig on it and you will quickly regret it.
    mikeacman

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