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  1. #1
    Join Date
    Feb 2003
    Location
    northwest of Atlanta, for now
    Posts
    273

    Carrier heat Pump

    Model 38AQ016500
    Air handler 40RR016
    Coils are clean, drive belt good, filters okay.
    Ambient 35°, HP 165#, LP 31#, line temps 127 and 81.

    I put 18 pounds of R22 in it and ran out. System holds ~37# when there is a 25 foot line set. I have to go back with more R22.

    Low charge?

    Thanks.

  2. #2
    Join Date
    Dec 2002
    Location
    SouthEast NC ICW & Piedmont Foothills
    Posts
    7,635
    are those psi & temp before or after adding refigerant
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  3. #3
    Join Date
    Feb 2003
    Location
    northwest of Atlanta, for now
    Posts
    273
    Quote Originally Posted by dandyme View Post
    are those psi & temp before or after adding refigerant
    After. Actually, the pressures didn't change after the 18 pounds. The temps did a little. The unit was locked out when I arrived. I turned it off and back on at the disconnect to restart it.






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  4. #4
    Join Date
    Jul 2006
    Location
    Philly
    Posts
    63

    Question

    Was it locked out on the safety circuit CLO ( LP, HP, Discharge Temp ) etc. or the crankcase heater CLO?

  5. #5
    Join Date
    May 2004
    Location
    Los Angeles, CA
    Posts
    1,560

    Stop chargeing....your going to have to recover all the rerigerant back out of the sy

    Dear Heatair,

    Based on the limited diagnostic data you posted your subcooling for this system is approximately 49 degrees F and your superheat is approximately 72 degrees F.

    This system is extremely overcharged….unfortunately by you and the evaporative section is starving which means most likely one thing………….

    You have a refrigeration restriction somewhere between where you measured the liquid line and suction line temperatures. Most provable places are the liquid line filter/drier or metering device (fixed orifice or TXV).

    Hope this helps……….

    Respectfully Submitted,
    John J. Dalton CM

  6. #6
    Join Date
    May 2004
    Location
    Los Angeles, CA
    Posts
    1,560
    Dear Heatair,

    Please let us know which part is causing the restriction when you find out. Thank you.

    Respectfully Submitted,
    John J. Dalton CM

  7. #7
    Join Date
    Feb 2003
    Location
    northwest of Atlanta, for now
    Posts
    273
    Quote Originally Posted by john dalton View Post
    Dear Heatair,

    Based on the limited diagnostic data you posted your subcooling for this system is approximately 49 degrees F and your superheat is approximately 72 degrees F.

    You have a refrigeration restriction somewhere between where you measured the liquid line and suction line temperatures. Most provable places are the liquid line filter/drier or metering device (fixed orifice or TXV).
    It's not the Filter Drier. I checked the temp drop across it.





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  8. #8
    Join Date
    May 2004
    Location
    Los Angeles, CA
    Posts
    1,560
    Dear Heatair,

    Although the refrigeration restriction can be anywhere between the points that where checked for temperature on the liquid and suction lines, the most common place would then be the metering device (fixed orifice or TXV). Please continue to inform us of your progress.

    Respectfully Submitted,
    John J. Dalton CM

  9. #9
    Join Date
    Feb 2003
    Location
    northwest of Atlanta, for now
    Posts
    273
    Quote Originally Posted by john dalton View Post
    Dear Heatair,

    Although the refrigeration restriction can be anywhere between the points that where checked for temperature on the liquid and suction lines, the most common place would then be the metering device (fixed orifice or TXV). Please continue to inform us of your progress.

    Respectfully Submitted,
    John J. Dalton CM
    Mr Dalton,

    You specifically stated the restriction may be in the filter-drier OR the metering device. I simply stated the Drier was clear.

    I went back out there Monday. It was again off on one of the safety circuits (High pressure, loss of charge, or Internal) or the control logic. For the night, I jumped out the safeties and will go back this AM to see the status as well as restore the safeties.

    While I was there, I ran it in heat mode:
    HP 250#
    LP 51#
    HT line 172°
    LT line 97.8°
    amb temp 60.6° (intake air to coil)
    Disc air 48.4° (disc air from coil)

    The building was warm, so I ran it in cool mode. After the temps and pressures stabilized, this is what I got:
    HP 195# (sat temp 100°
    LP 52# (sat temp 28°)
    HT 65° (yes, 35° SH)
    LT 38.6 (10° SC)
    amb temp 63°
    Disc air 89°

    Again, in heating mode:
    HP 255#
    LP 53#
    HT line 176.5°
    LT line 98.4°
    amb temp 65.6° (intake air to coil)
    Disc air 50.6° (disc air from coil)

    All temp were taken outside the condenser and allowed to stabilize. In the cooling mode, there would be some spikes from liquid hitting the walls of the suction line(?!), those numbers were averaged.

    I know that superheat at the condenser should be 15-20 degrees and at the evap about 8-10 degrees and subcooling at the condenser should be 15-20 degrees.





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  10. #10
    Join Date
    Aug 2006
    Posts
    2,609
    Quote Originally Posted by heatair View Post
    For the night, I jumped out the safeties and will go back this AM to see the status as well as restore the safeties..
    You fixed it, just leave it like that. When the customer calls for the next failure replace indoor unit, outdoor unit, line set, wiring, and thermostat. If you have to jump out anything on the new unit, just smile as there's nothing like job security for all of us.

  11. #11
    Join Date
    Mar 2005
    Posts
    188
    hey Heatair,
    Look closer at what You posted . In cooling mode you unit discharge air is 87 F and in heating mode 50?

  12. #12
    Join Date
    Feb 2003
    Location
    northwest of Atlanta, for now
    Posts
    273
    Quote Originally Posted by madhat View Post
    You fixed it, just leave it like that. When the customer calls for the next failure replace indoor unit, outdoor unit, line set, wiring, and thermostat. If you have to jump out anything on the new unit, just smile as there's nothing like job security for all of us.
    Nah.....

    Already been there and out it back together, except the HP switch is out of the circuit. I've seen the Carrier Logic circuits do weird because of the amp reading it supposedly does.

    Good try....





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  13. #13
    Join Date
    Feb 2003
    Location
    northwest of Atlanta, for now
    Posts
    273
    Quote Originally Posted by uke View Post
    hey Heatair,
    Look closer at what You posted . In cooling mode you unit discharge air is 87 F and in heating mode 50?
    Good point, I should have pointed out these were the readings totally at the outside unit, nothing inside.






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