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  1. #1
    Join Date
    Jun 2010
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    Houston, Texas
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    Carrier 6 Ton RTU High Suction Pressure

    R22, 6 ton light commercial straight cooling RTU, 1 month nearly new Danfoss scroll compressor, previous tech also converting the original fixed orifice to TXV two weeks ago, cleaned evaporator and condenser coil, blower and OD fan motor in normal operation. 80F outdoor dry bulb, condenser fan rejecting air temp 95F. AC return air 75F, supply air temp 65F at register outlet, discharge pressure 215 psi, discharge temp 229.8F, suction pressure 101psi, with 4F superheat 6 inch before compressor. 21F subcool. compressor is running at higher than normal temp. Now come to the question, will a faulty TXV cause high suction pressure due to stuck open like 90%? no matter how to adjust the superheat, nothing happen to the low side pressure. need some advise here, thanks.

  2. #2
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    Sep 2002
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    Virginia
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    Did the tech add any more freeezon than label says ?

    Im really confused how the discharge is 226 F , if the txv is wide open sending back really cold gas ...

    Make sure they didnt send you a bigger compressor

  3. #3
    Join Date
    Sep 2007
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    NH
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    Sounds like a bad compressor to be. With a flooding txv u will have high discharge and low superheat. Could try slowing down the blower or running it with no blower to see if suction pressure is still really high.

  4. #4
    Join Date
    Nov 2006
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    Southeastern Pa
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    Part of what I'm wondering is was the TXV conversion done properly...
    [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:







  5. #5
    Join Date
    Oct 2018
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    Quote Originally Posted by jumstar View Post
    21F subcool.
    I’d start here...


    Sent from my iPhone using Tapatalk

  6. #6
    Join Date
    Sep 2002
    Location
    Virginia
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    Hold up

    Theres some story we arent hearing

    New compressor 1 month ago

    TXV swap 2 weeks ago ....

    Whats the whole story

  7. Likes jumstar liked this post
  8. #7
    Join Date
    Jun 2010
    Location
    Houston, Texas
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    Thread Starter
    I doubt that too, but hard to tell

  9. #8
    Join Date
    Jun 2010
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    Houston, Texas
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    Thread Starter
    I attempt to remove nearly 1 lb of r22, same condition exists, right size compressor

  10. #9
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    Jun 2010
    Location
    Houston, Texas
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    Thread Starter
    Will try to run without blower when I get back this morning

  11. #10
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    Jan 2010
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  12. #11
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    Typically we also like the model and serial number for the unit in question and the label information from the new compressor might also be helpful along with information about the TXV itself.... from its label.

    Which refrigerant is the original refrigerant for the unit from the manufacturer, and is a different refrigerant being used now?
    [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:







  13. #12
    Join Date
    Nov 2011
    Location
    East Side
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    22* discharge SH is low for a scroll compressor.

    Recover charge and weigh.

    Sounds like the conversion is the culprit. The new distribution header should have an orifice, sized for the tonnage. Also the distribution tube size, and number of tubes Needs to be sized for the correct pressure drop. Got any pics of the conversion?

  14. #13
    Join Date
    Jun 2010
    Location
    Houston, Texas
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    Thread Starter
    Quote Originally Posted by timebuilder View Post
    Typically we also like the model and serial number for the unit in question and the label information from the new compressor might also be helpful along with information about the TXV itself.... from its label.

    Which refrigerant is the original refrigerant for the unit from the manufacturer, and is a different refrigerant being used now?

    Using the original R22



    Sent from my iPhone using Tapatalk

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