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  1. #27
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    Quote Originally Posted by hvacrmedic View Post
    On a TXV system the charge is generally adjusted to achieve proper subcooling, not by condenser TD. Just forget the condenser TD and get the unit charged. Condenser TD is not a constant. Don't treat it like it is.
    yes, i am also working in the same way . first goal is achieve the sub cooling; at the same time, when charging to get the subcooling, the condenser pressure do not raise above max.discharge pressure.

  2. #28
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    Thread Starter
    Quote Originally Posted by hands View Post
    I have never heard of fan blade placement affecting subcooling, this is good to know. So how do you find out the proper placement of the fan blade?
    there is a possibility when fan blade place in the wrongway,it means if thereis no desighn air flow definity reduce the condensation and subcooling. but, in my case, it is correct placing.

  3. #29
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    Feb 2008
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    What I understand that the local manufactures have no any engineering ideas to design a coil. I asked them, what is the internal volume of condenser coil, total heat rejection...etc. they don’t have any ideas. Truth be told they don’t know how to check the subcooling! After these issues with them, they purchased a testo 550 meter and told me they will practice onwards. when they get a order They just follow the ditto, and above they don’t care anything.

  4. #30
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    Sep 2019
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    Quote Originally Posted by moideen View Post
    Replaced with new condenser coil for a packaged unit. R-22 txv system. After commissioning, I checked its operation parameters and found sub cooling is not enough. it is below 2F. local manufacture says that the coil is the copy past of the old unit. Same physical measurement of the old condenser coil. What would be the errors of the new coil? The discharge pressure is maximum, condenser split is 30F, so cannot charge more refrigerant. and the condenser fan is ok. Any comments really appreciated. thanks
    Is the correct condenser fan motors on unit? Were you getting the same exact issue prior to coil replacement? What''s your superheat at the compressor?

    When you say condenser split is 30 .. is that the air leaving is 30 degrees higher than entering?

  5. #31
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    Quote Originally Posted by superheatmaster View Post
    When you say condenser split is 30 .. is that the air leaving is 30 degrees higher than entering?
    This is Delta T.

    Split is the air entering (ambient) temperature compared to the condensing temperature at the pressure being measured. This is an old-school method of top off charging which was replaced by measuring subcooling. For low-SEER equipment, 30 degrees was used as a benchmark.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
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  6. #32
    Join Date
    Jul 2005
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    Quote Originally Posted by moideen View Post
    yes, i am also working in the same way . first goal is achieve the sub cooling; at the same time, when charging to get the subcooling, the condenser pressure do not raise above max.discharge pressure.
    There is no such thing as max discharge pressure, unless you’re tripping out on high pressure. Max would be whatever the safety is set for.

  7. #33
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    Sep 2002
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    Maybe he meant to say discharge TEMPerature ...

    Im wondering why the coil was replaced to begin with ....

  8. #34
    Join Date
    Nov 2011
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    Quote Originally Posted by moideen View Post
    What I understand that the local manufactures have no any engineering ideas to design a coil. I asked them, what is the internal volume of condenser coil, total heat rejection...etc. they don’t have any ideas. Truth be told they don’t know how to check the subcooling! After these issues with them, they purchased a testo 550 meter and told me they will practice onwards. when they get a order They just follow the ditto, and above they don’t care anything.

    So, basically, the people that designed and built the replacement condenser coil don’t have NO clue what they are doing.

    You have been a part of this forum for some time. Maybe you should offer to give them your expertise!! ...for a price of course.

  9. #35
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    Sep 2002
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    Virginia
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    So he's working on a OLD unit that cant get new parts for any longer ? So had one made ?

  10. #36
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    Nov 2011
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    Apparently...

  11. #37
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    Jul 2019
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    Oklahoma home its in the name
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    I know its a foreign thought here in the US.
    Quote Originally Posted by Snapperhead View Post
    So he's working on a OLD unit that cant get new parts for any longer ? So had one made ?
    Sent from my rotary telephone using Tapatalk

  12. #38
    Join Date
    Nov 2006
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    Southeastern Pa
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    He probably needed a better coil supplier....
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

    AOP Forum Rules:







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