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  1. #1
    Join Date
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    please tell me what's wrong -

    Refrigerant: R-407C
    Type of Metering Device: Alco TCLE
    Ambient Temperature: 96
    Head Pressure: 245 lbs. (107)
    Condenser Air Out Temp: 106
    Liquid Line Temperature: 91
    Liquid Subcooling: 15
    Suction Pressure: 54 lbs. (34)
    Suction Line Temp: 65
    Suction Superheat: 31
    Return Air Temperature: 74
    Evaporator Leaving Air Temp: 57
    Evap air ∆T: 17

    What is wrong with this system? What should I do to fix it?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  2. #2
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    Aug 2016
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    Find the restriction

  3. Likes mythreeegirls liked this post.
  4. #3
    Join Date
    Nov 2011
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    Since when do you need to ask how to diagnose refrigerant system issues?



    Trick question?

  5. Likes lions_lair, idratherbsailing, icy78 liked this post.
  6. #4
    Join Date
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    Quote Originally Posted by Saturatedpsi View Post
    Since when do you need to ask how to diagnose refrigerant system issues?



    Trick question?
    That was my thought, maybe he's starting to get Oldtimers disease, you know when you forget to remember what you just forgot. lol Shouldn't laugh it's not funny. I'll walk into a room and forget what I went in for, it's terrible when it's the bathroom. Or go all the way out to the truck only to forget what you wanted, so ou grab some stuff and head back only to remember once you get back downstairs.

    Sorry Mikey what do you want to fix?

    Air flow?
    WB?
    What else do we ask DIYers or newbies for that he hasn't posted?

  7. #5
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    Thread Starter
    An interesting diagnosis - please tell me how you came to that conclusion.

    PHM
    ------



    Quote Originally Posted by Blake79 View Post
    Find the restriction
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  8. #6
    Join Date
    Sep 2002
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    Thread Starter
    How it started:

    About a week or so ago I woke up before dawn and thought: "there is something wrong". So I laid there and I listened and I could hear my two condensing units running outside.

    One is a R-410 Goodman 018 condenser piped to an 024 Unico air handler.

    The other is an early 1980's Coleman 5 ton condensing unit with the 15K BTU rotary compressor I salvaged out of an old window box grafted into it. Oil is a blend of mineral, POE, and Supco 88. Refrigerant is R-407C.

    The upstairs unit cycled off - the 1st floor unit continued to run.

    That happened several times over several nights and each time I concluded that it was the frankensteined Coleman which was twitching my mechanical intuition alarm.

    I did nothing about fixing it but I did note that on 95+ days the 1st floor temp drifted from the 73 setpoint to 74, and sometimes even to 74 by late afternoon.

    Today I only had two No-cooling!!!!! calls to do so this afternoon I set up my 8000 CFM work fan and set up the test gear on the old Coleman.

    Then I posted the data so as to be able to discuss it all with you all.

    It's not a trick question - just a question. <g>

    PHM
    -------


    Quote Originally Posted by BNME8EZ View Post
    That was my thought, maybe he's starting to get Oldtimers disease, you know when you forget to remember what you just forgot. lol Shouldn't laugh it's not funny. I'll walk into a room and forget what I went in for, it's terrible when it's the bathroom. Or go all the way out to the truck only to forget what you wanted, so ou grab some stuff and head back only to remember once you get back downstairs.

    Sorry Mikey what do you want to fix?

    Air flow?
    WB?
    What else do we ask DIYers or newbies for that he hasn't posted?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  9. #7
    Join Date
    Dec 2002
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    in a house, Appomattox, Va.
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    oversized evap?
    Col 3:23


    questions asked, answers received, ignorance abated

  10. #8
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    Aug 2016
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    LL cooler than ambient, low condensor split, low SP high SH

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  12. #9
    Join Date
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    Quote Originally Posted by Poodle Head Mikey View Post
    Refrigerant: R-407C
    Type of Metering Device: Alco TCLE
    Ambient Temperature: 96
    Head Pressure: 245 lbs. (107)
    Condenser Air Out Temp: 106
    Liquid Line Temperature: 91
    Liquid Subcooling: 15
    Suction Pressure: 54 lbs. (34)
    Suction Line Temp: 65
    Suction Superheat: 31
    Return Air Temperature: 74
    Evaporator Leaving Air Temp: 57
    Evap air ∆T: 17

    What is wrong with this system? What should I do to fix it?
    With the LL below ambient, you likely have a restriction in the condenser.

    Find the liquid header in the condenser and check the feeds into it. The coldest one will be where the issue is coming from.


    Sent from my iPhone using Tapatalk

  13. #10
    Join Date
    Dec 2009
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    maroon lazyboy
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    Why is the condensed liquid cooler than outdoor ambient?

    Head pressure seems a little low for the ambient.

    Can you adjust the txv superheat?

  14. #11
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    maroon lazyboy
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    Also condenser air out, is usually 1 or 2 warmer than condensing sat temp in my experience. Must be because of the discharge superheat.

  15. #12
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    Dec 2004
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    Wait a minute - is this the set up that you have with an EPR valve at the evap?


    Sent from my iPhone using Tapatalk

  16. #13
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    Sep 2002
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    Thread Starter
    And also: I had forgotten something -

    The evap on this system is a 3 ton horizontal A. I forget the brand right now but they come is an bright dimple-finish 'aluminum' case. Galvalume maybe?

    I originally set it up with an Alco take-apart TXV - a TCLE with a 2 ton cage assembly in it. But later I installed a 3 ton non-adjustable Sporlan TXV - I forget why now.

    The condenser approach is essentially zero - so I can try easing the subcooling up and forcing more capacity out of the valve with losing too much to higher head pressure. Obviously I can't adjust the TXV at this point. <g> But the SSH is clearly too high so something has to be done.

    I was just curious what you all suggested.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

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