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  1. #1
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    Nov 2005
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    How does water get into my refrigeration system

    Arrived to a call today to find one of the circuits (two scroll compressors) with what looked like water in the sight glasses. This system utilizes a water cooled shell and tube condenser. I have came across water in the refrigeration circuit several times, however I'm trying to find out exactly how this happens. In this case I found this on a maintance and the machine was not running on arrival. The refrigerant is 134A and this skid is used for DX high temperature (comfort cooling). The water pressure from the discharge of the condenser water pump is a constant 40 pound supply. So my question is this, if my refrigerant pressure stays higher then 40 pounds all the time how exactly does water enter into my refrigeration system. I was told that this is due to OSMOSIS. Can somebody tell me if this is true and exactly how this works. I have been looking into this, however mabey somebody can simply explain this to me.

  2. #2
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    When the bundle fails, the high pressure refrigerant leaks into the waterside until the pressures equalize, then the transfer will go both ways based on temperature difference.

  3. #3
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    I do not believe this is true because there was more refrigerant pressure when I hooked on to the refrigerant service valves then there was water pressure going through the shell and tube condenser. If your theory was correct then there should have been no water/moisture in the compressors until the pressures equalized. There was 60 pounds of refrigerant pressure at the service valves and only 40 pounds of water pressure at the shell and tube condenser. When I recovered the refrigerant from the sytem I recovered 32 pounds from a factory charge of 36 pounds. Not much refrigerant seemed to dissapear from the sytem. I at first thought like you until it was explained to me by an old instructor that this is the result of osmosis. And that the water pressure does not have to be greater then the refrigerant pressure to get water into your refrigerant.

  4. #4
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  5. #5
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    Quote Originally Posted by jpsmith1cm View Post
    Google "Bernoulli's Principle"
    Liquid or gas Pressure and velocity being inversely proportional has what to do with water being in a sight glass ?

    Ive got a A and P license and worked for 3 years on Grumman single engine aircraft so Im a little familliar with that concept. As it pertains to airfoils and caberetors anyway.

  6. #6
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    Quote Originally Posted by excel View Post
    Arrived to a call today to find one of the circuits (two scroll compressors) with what looked like water in the sight glasses. This system utilizes a water cooled shell and tube condenser. I have came across water in the refrigeration circuit several times, however I'm trying to find out exactly how this happens. In this case I found this on a maintance and the machine was not running on arrival. The refrigerant is 134A and this skid is used for DX high temperature (comfort cooling). The water pressure from the discharge of the condenser water pump is a constant 40 pound supply. So my question is this, if my refrigerant pressure stays higher then 40 pounds all the time how exactly does water enter into my refrigeration system. I was told that this is due to OSMOSIS. Can somebody tell me if this is true and exactly how this works. I have been looking into this, however mabey somebody can simply explain this to me.
    Osmosis ? Through copper ? Could be a small amount of moisture left over from some one doing sloppy maintenance.

  7. #7
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    Aug 2010
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    Quote Originally Posted by commtech77 View Post
    Liquid or gas Pressure and velocity being inversely proportional has what to do with water being in a sight glass ?

    Ive got a A and P license and worked for 3 years on Grumman single engine aircraft so Im a little familliar with that concept. As it pertains to airfoils and caberetors anyway.

    A good venturi type vacuum pump that runs on compressed air can pull 27" of vacuum.

    If something is getting in through a leak, I would think there's enough air to affect pressure and maybe moisture indicator will show how dry the refrigerant is.

  8. #8
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    Huh ? No. Most techs measure vacuum in microns not inches.

    Its a water cooled condensor and there is water in a sight glass. Hmmmm ?

    Still waiting for a explanation to how Bernoulis principle has amything to do with a busted condensor.

  9. #9
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    Jun 2003
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    Chicago, IL
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    Quote Originally Posted by commtech77
    Still waiting for a explanation to how Bernoulis principle has amything to do with a busted condensor.
    If the refrigerant is flowing past the leak area fast enough it's pressure can be lower than the static pressure at the gauge

    I don't think it would be more than 10 psi or so. Also refrigerant doesnt flow fast through a shell and tube condenser so I don't know if it can explain your situation

  10. #10
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    Quote Originally Posted by craig1 View Post
    If the refrigerant is flowing past the leak area fast enough it's pressure can be lower than the static pressure at the gauge

    I don't think it would be more than 10 psi or so. Also refrigerant doesnt flow fast through a shell and tube condenser so I don't know if it can explain your situation
    I think what JP was implyimg was refrigerant flow through the condensor was causing a low pressure condition that dipped well below the 40 psi water pressure.

    That doesnt explain why a shell cooler is leaking. A good vacum would pull water through the heat exchanger.

  11. #11
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    Nov 2005
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    California
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    This is not a small amount on moisture. Water in the the oil sight glass of a scroll 15 ton compressor is not a little water. I removed the main removable shell drier and got water drops coming out of the canister when i was pulling it apart. Both moisture sight glasses were also showing moisture in the system. One sight glass was in the liquid line and the other was in the oil line. This system utilizes a TRAX oil system to help maintain oil level in the two 15 ton parallel scrolls.

  12. #12
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    It doesnt sound good. Sounds like the coolers leaking.

  13. #13
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    Feb 2010
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    NE Alabama
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    If it's leaking it's leaking and the scientific principle behind the leak path isn't the big issue here. If you have found water several times as you stated why isn't as important as where. In a sealed water cooled system as you find on an ac system providing cooling on yachts with a jacketed condenser any water in refrigerant lines is a leak between tubing systems. In larger systems with gasketed heads the leak could be in the gasket or gasket seating surfaces and torque of head bolts would just be one of many reasons for leaking. It's your system and instead of struggling with why find the leak and worry about why later. Scientific principles are just best guesses given with data provided and as such are indicators and not irrefutable answers.

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