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  1. #1
    Join Date
    Sep 2004
    Posts
    20

    High pressures high superheat is what now?

    I looked at a 12 year old 10seer Trane R22 split system today and could not solve the problem.
    Complaint: AC runs and cools but not sufficiently.
    First thing I did was to check the pressures: 90 and 475 on R22 system, 82 degree outside ambient.
    Then I took Superheat 38 and Subcool 25. BTW this is a distributer tube metering device so I know to concentrate on the Superheat.
    Next I took temperature differentials across the Condenser 25 and Evap 9.
    I looked around to see how dirty the coils other parts are and the coils did not look especially dirty so I did nothing to clean them. The furnace fan did have much buildup on the blades though.

    What I'm stuck on is that both pressures are very high and the superheat is very high also. Advise please.

    BTW how do I make a degree sign on the keyboard?

  2. #2
    Join Date
    Feb 2008
    Location
    Western NC
    Posts
    2,504
    You need to start by cleaning both coils and the fan blades. Then you need to take an airflow measurement.(not the 5 finger test either). Get your CFM proper and take it from there.

    You make the * symbol by using the number 8 on the keyboard. Shift + 8 = *
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    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  3. #3
    Quote Originally Posted by nlovas View Post
    I looked at a 12 year old 10seer Trane R22 split system today and could not solve the problem.
    Complaint: AC runs and cools but not sufficiently.
    First thing I did was to check the pressures: 90 and 475 on R22 system, 82 degree outside ambient.
    Then I took Superheat 38 and Subcool 25. BTW this is a distributer tube metering device so I know to concentrate on the Superheat.
    Next I took temperature differentials across the Condenser 25 and Evap 9.
    I looked around to see how dirty the coils other parts are and the coils did not look especially dirty so I did nothing to clean them. The furnace fan did have much buildup on the blades though.

    What I'm stuck on is that both pressures are very high and the superheat is very high also. Advise please.

    BTW how do I make a degree sign on the keyboard?

    Those pressures are scary. Condenser fan running? Overcharged or noncondensables.

  4. #4
    Join Date
    Sep 2004
    Posts
    20
    Condenser fan is running within amperage. Compressor is at 1 amp over rating. I did not amp furnace fan.
    I plan on cleaning both coils and the furnace fan tomorrow.

    If there was an overcharge could the superheat be as high as it is (38)?

  5. #5
    Join Date
    Apr 2007
    Posts
    623
    plugged condenser coil + possible overcharge seems likely. What did the condenser coil look like as far as cleanliness.

  6. #6
    Join Date
    Apr 2007
    Posts
    623
    let us know how this one comes out.

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,120
    Quote Originally Posted by iraqveteran View Post

    You make the * symbol by using the number 8 on the keyboard. Shift + 8 = *
    Dude. * is not the symbol for degree.
    is the symbol for degree.
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  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,120
    Do a frost test on the indoor coil.

    While holding the alt key down, enter 0176 to make the ° symbol.
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    How many times must one fix something before it is fixed?

  9. #9
    Join Date
    Aug 2002
    Location
    manitowoc wisconsin
    Posts
    4,943
    High suction & high head with 25 deg subcooling.
    Dumb question.
    Is the heat on?
    Take your time & do it right!

  10. #10
    Join Date
    Feb 2008
    Location
    Western NC
    Posts
    2,504
    holy freakin crap beenthere.....



    I never knew I could make the with the keyboard...



    What else ya got? I need to learn how to type here. Come on...entertain my brain
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  11. #11
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,120
    Dude, let the alt key guy you.

    alt 0188=¼, alt 0189=½, alt 0190=¾
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  12. #12
    Join Date
    Jul 2008
    Location
    RTP North Carolina
    Posts
    81
    The info you have provided points to non-condesables, possible mixed refrigerants, or poor condensor coil performance. I wouldn't necesarily suspect overcharging because of the high superheat.

    As previously suggested your first step should be a cleaning of the system, including both coils, and fan blade/squirrel cage.

  13. #13
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,665
    check to see if the return air fall off in the attic, is the condensor fan blade turning the correct rotation and wash the condensor

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