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Thread: Refrigeration

  1. #21
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    My book is almost 40 years old. Interestingly enough, I pulled it out a week ago, then put it back this morning.

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    Quote Originally Posted by timebuilder View Post
    And buy a copy of the book.....
    I do a triple evac with nitro to remove non condensables.

  2. #22
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    Quote Originally Posted by BBeerme View Post
    I'm just saying that there is too much we do not know. Sort of like my co-workers who do not even use the proper terminology. I keep telling them that I will give you the answer to your question, but your question may not be worded properly so you will get the wrong information.

    Gawd, I wish my co-workers would come on this forum just so they could learn how to speak properly, I mean, use the right words for what they are trying to ask.
    Off topic but I’d like to hear some examples of the poorly formed questions from your coworkers. I still cringe when people use the term Freon for every refrigerant.

  3. #23
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    I have the same book!!!!we are giving away our age!!Do you have Doolins trouble shooting Bible,Also an old ie but goodie!! That was the book that was used in our tech school back in 1978

  4. #24
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    If there is no sight glass, just torch the reciever. Checking subcool on a reciever system is kinda pointless for the most part.

  5. #25
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    Had some weird subcool readings from a tech, I asked him where his temp probe was. He said the discharge line. Told him to put it on the liquid line, he said that's where it is, on the discharge line.

    Then there was so other weird pressure readings.

    So I had to actually drive over to that job and help him out. First I had to explain the difference between a discharge line and the liquid line.

    Then I found the motor master probe on stage two condenser, stat not wired properly through the economizer, bulbs for TEV's on wrong suction line, dampers in return closed, and both circuits way over charged.

    It was a new install by others. Customer threw that contractor out, then called us.


    Quote Originally Posted by Oi! Rodgers View Post
    Off topic but I’d like to hear some examples of the poorly formed questions from your coworkers. I still cringe when people use the term Freon for every refrigerant.
    I do a triple evac with nitro to remove non condensables.

  6. #26
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    I pulled out the book last night.It was published in 1976.Interesting enough, that is still a major book ,still used in tech schools today.It is now up to edition number 20.last printing 2016. The book on Amazon goes for about $116.00. I may have to get the new versions it is much more up to date,The old version still allows venting of freon!!!

  7. #27
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    Quote Originally Posted by timebuilder View Post
    And buy a copy of the book.....
    This is the one I was suggesting....

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    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

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  8. #28
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    Refrigeration is the process of cooling a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is rejected at a higher temperature).

  9. #29
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    Why does it need to be rejected at a higher temperature? That doesn't make sense.


    Quote Originally Posted by jackfowler View Post
    Refrigeration is the process of cooling a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is rejected at a higher temperature).
    I do a triple evac with nitro to remove non condensables.

  10. #30
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    Just to be clear, I've worked on a lot of environmental chambers that ran at temps much greater than what the heat was rejected to.

    Then there was that convenience store at 105*F, and once I got that system on line, the refrigeration was rejecting heat to the 60*F San Francisco foggy ambient. Calculate your TD's on that one, and you'll find your suction and discharge pressures nearly the same, relatively speaking.


    Quote Originally Posted by BBeerme View Post
    Why does it need to be rejected at a higher temperature? That doesn't make sense.
    I do a triple evac with nitro to remove non condensables.

  11. #31
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    I'm the only one who doesn't understand your point.

  12. #32
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    Quote Originally Posted by logan_paul View Post
    I'm the only one who doesn't understand your point.
    In my example above, the heat is being rejected at a much lower temperature.
    I do a triple evac with nitro to remove non condensables.

  13. #33
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    First heard about the Dick Wirz book here and can wholeheartedly recommend as well.
    Currently in the 3rd edition of print, sample chapters are available for free trial at the Google Play store.
    The entire book is also available in e-book form.
    Not my cup of tea as I prefer the printed page.

    Note about superheat, the discussion needs to be narrowed as to which superheat your cohort is measuring.
    At the evaporator outlet, or at the compressor inlet?

  14. #34
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    Quote Originally Posted by jackfowler View Post
    Refrigeration is the process of cooling a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is rejected at a higher temperature).
    I think it's referring to the condensing temperature being higher than ambient and heat is rejected.

  15. #35
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    Quote Originally Posted by BBeerme View Post
    My book is almost 40 years old. Interestingly enough, I pulled it out a week ago, then put it back this morning.

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    BBeerme, my copy of that book is Copyrighted in 1968. Purchased in 1969. Modern Refrigeration & AC,,,
    Gleng, my copy of that book is Copyrighted 1963. Purchased in 1972. Doolins Bible,,,
    Timebuilder, my copy of that book is Copyrighted 2010, Purchased in 2016..Commercial Refrigeration for AC Techs,,,,

    All a Good Read!

  16. #36
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    30 degree superheat is high for almost all applications even at the compressor it is at the max most comp manufactures want to see.

    It IS possible that it is ok for some situations, however it makes no difference what so ever because you can't use ONLY subcooling and superheat to evaluate a refrigeration system or its performance.

    A simple example using the OP number of 30 sh. It makes a huge difference what your delta is over the evaporator, if you have 10 degrees then the sh may simply be a high load on the coil, if you only have 3 degrees you dont have enough refrigerant IN THE EVAPORATOR, you MIGHT not have enough or it may be somewhere else within the system.

    SC AND SH are two pieces of info, about 20 percent of the information you need to figure out what is going on.

  17. #37
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    I do triple evacuation with nitro to remove non-condensable. I did not use other methods.

  18. #38
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    Quote Originally Posted by Jon30 View Post
    I do triple evacuation with nitro to remove non-condensable. I did not use other methods.
    I thought that nitro is a non-condensable. So there has to be something more involved here.

  19. #39
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    Quote Originally Posted by Jon30 View Post
    I do triple evacuation with nitro to remove non-condensable. I did not use other methods.
    Quote Originally Posted by TechmanTerry View Post
    I thought that nitro is a non-condensable. So there has to be something more involved here.

  20. #40
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    I always get a kick out of it when someone says that, LOL.


    Quote Originally Posted by Jon30 View Post
    I do triple evacuation with nitro to remove non-condensable. I did not use other methods.
    I do a triple evac with nitro to remove non condensables.

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