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  1. #51
    Join Date
    Dec 2007
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    Re: Sub cooled r22 still flashing?



    scan0001.jpgDrew tis picture may satisfy you in regards to sub cooled liquid & liquid/vapour on P/E diagram



  2. #52
    Join Date
    Apr 2001
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    New Port Richey, Florida - USA
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    Re: Sub cooled r22 still flashing?

    There is no concept in refrigeration that confuses more people than the static gas law which says you can't have superheat in the presence of liquid nor subcooling in the presence of vapor. The key word here is static, meaning non-energized. As soon as energy is applied, it all changes. It is only true when the system is off.

    In a functioning system, it is entirely possible to have superheated vapor bubbles surrounded by subcooled liquid and subcooled liquid droplets surrounded by superheated vapor... and this is in fact common in portions of the liquid and suction lines.

    Velocity carries the bubbles and droplets far past the points where you might expect them to disappear. That's why you need substantial amounts of subcooling to clear a sight glass and substantial amounts of superheat to avoid flooding the compressor. How much you need depends on the velocity.

    It varies, but essentially you need 10-15F SC (5.5-8.5K SC) to clear the sightglass... and sometimes a little more. If any of the TXV's are flooding the coil, it should be fixed before you try to clear the sight glass.
    Last edited by Gary; 23-03-2013 at 04:45 AM.

  3. #53
    Join Date
    Apr 2001
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    Re: Sub cooled r22 still flashing?

    You might find this thread helpful:

    http://www.refrigeration-engineer.co...rigeration-101

  4. #54
    Join Date
    Apr 2008
    Location
    Tasmania
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    Re: Sub cooled r22 still flashing?

    Thanks Ranger1 and Gary. I like the sound of a static gas law as opposed to the other type.
    ill see further what the inter web has to say.
    The more I learn the less I know......

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