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  1. #1
    Join Date
    Jan 2011
    Location
    Bartlesville, Ok
    Posts
    115

    Charging Opinion

    I do controls, but I have been watching and learning the refrigeration side. Plus I have studied the digital gauge issues and watched the videos online. Here is my question. I have never seen the guys I work around charge to a temperature, just pressure. I have watched them on small pack units, large pack units, condensers, chillers, you name it. Some have over 20 years in the business. I am curious as to the pros around here's take on that.

    Just Curious.

  2. #2
    Join Date
    Sep 2012
    Location
    Texas
    Posts
    23
    gotta charge by superheat/subcooling if you wanna do it right

  3. #3
    Join Date
    Jan 2005
    Location
    Akron
    Posts
    1,204
    If you want to do it right you pay attention to saturation temperature of both coils (corresponds to pressure) and to superheat and subcooling. You can easily have a system that is running a low coil temp and has low airflow, or a dirty condenser that is running high head, but correct superheat and subcooling. A technician that does not pay attention to those things will charge to the airflow or the coil conditions. You should be able to determine what the saturation temperature and the pressure are before you even hook up the gauges. Simply put, if you do not know what they should be, what difference does it make what they are? Superheat and subcooling tell you a lot, but definitely not the whole picture. Take a look at these pages, they are geared toward A/C, but the same principals are true with refrigeration.

    http://www.trutechtools.com/RefrigerantCharging
    JLB,

  4. #4
    Join Date
    Apr 2011
    Location
    Coastal Maine
    Posts
    885
    Very well put Jim.

    I too am an old dude. I see too many techs today that have subcool and superheat so beaten into their heads at Trade/Tech Schools, that they forget about everything else. The proper way to charge is to look at the whole picture. I guarantee that those 20+yr techs are looking at more than just pressure. It may be subtle, but you don't charge chillers without looking at everything.

    Keep watching and asking questions. Someone has to do this stuff when us old guys are too worn-out to do it anymore.

  5. #5
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    That's funny Jim I was just watching your video on combustion analysis. I just posted a question about it, I would like a better understanding of what I'm looking at.


    Sent from my iPhone using Tapatalk

  6. #6
    Join Date
    Jan 2005
    Location
    Akron
    Posts
    1,204
    Quote Originally Posted by Joehvac25 View Post
    That's funny Jim I was just watching your video on combustion analysis. I just posted a question about it, I would like a better understanding of what I'm looking at.


    Sent from my iPhone using Tapatalk
    Ok I give up. Where did you post your question?
    JLB,

  7. #7
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    Oh sorry tech to tech, thanks for responding!


    Sent from my iPhone using Tapatalk

  8. #8
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    It is tech to tech resi, looks like some people posted links to your site.


    Sent from my iPhone using Tapatalk

  9. #9
    Join Date
    May 2002
    Location
    Baton Rouge, Louisiana
    Posts
    3,959
    Quote Originally Posted by meplumber View Post
    Very well put Jim.

    I too am an old dude. I see too many techs today that have subcool and superheat so beaten into their heads at Trade/Tech Schools, that they forget about everything else. The proper way to charge is to look at the whole picture.
    Same here, totally agree

    Also your superheat and subcooling isn't some number that someone tells you and that goes for every unit...................

    You use the manufacturers SPECIFIED superheat and subcooling info.
    Quote Originally Posted by MatrixTransform View Post
    very soon it is you that will be pwned

  10. #10
    Join Date
    May 2012
    Location
    Westminster, Colorado
    Posts
    13
    Superheat and Subcooling are necessary for any proper charge. This has never been more true than with today's high-tech/high efficiency equipment. There are a lot of tools today that make it easier and faster than in the past (ie. digital manifolds and system analyzers) but remember that you still have to know what these tools are doing for you. Technology is great but understanding how and why this technology works is much better.

    Anytime I want to trust blindly in technology, I just think about those people who try to sue GPS companies because they drove into a lake when their GPS told them to.

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