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  1. #1
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,567

    So... What's the problem here?

    Hopefully the picture I took of the DRSA is adequate to provide all refrigerant side data.

    Problem is this:

    Dual temp single deck case would NOT hold temp in LT mode. Did a 'fair' job in MT.

    Tech#1 was out and condemned the powerhead and when that did nothing, replaced the whole TXV. When THAT didn't work, I was called in.

    Cut in a pressure tap and SG on the liquid line to confirm quality of liquid and the pic I posted gives the results. Sightglass was perfectly solid.


    So. Fire away.
    Attached Images Attached Images  

  2. #2
    Join Date
    Sep 2005
    Location
    Texas
    Posts
    2,793
    restriction in 1 or more distributor cap tubes?

  3. #3
    Join Date
    Dec 2007
    Location
    Ohio
    Posts
    2,875
    Seeing as how I am a former resi guy and new to the refer tech gig, I'm
    going to take baby steps on this one....

    Am I correct in thinking that suction PSI is too low?

    (or do I need to head back to class?)
    I need a new signature.....

  4. #4
    Join Date
    Sep 2006
    Location
    Chicago
    Posts
    474
    Quote Originally Posted by air2spare View Post
    restriction in 1 or more distributor cap tubes?
    I was thinking the same. Maybe the nozzle is plugged. Or possibly a plugged external equalizer line for the txv...
    Last edited by dangpgt97; 12-05-2010 at 10:31 PM.

  5. #5
    Join Date
    Sep 2010
    Location
    Madison WI
    Posts
    77
    What type of txv ? is their an EPR to tell the system if it's MED or LT? I have seen some with a solenoid by pass.

  6. #6
    Join Date
    Feb 2003
    Posts
    1,166
    Liquid line drier in case was partially plugged, S.G. was cut in before drier??

    What are the components in each case?
    Suction line solenoid with 90 degree EPR for MT operation?
    Watts New, Ohm My, I been Electrically Commutated. Are U2.

  7. #7
    Join Date
    Apr 2010
    Location
    Richmond, Virginia
    Posts
    311
    CRO valve not set correctly or switchover solenoid not working properly

  8. #8
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,567
    Quote Originally Posted by Herb1025 View Post
    What type of txv ? is their an EPR to tell the system if it's MED or LT? I have seen some with a solenoid by pass.
    Externally equalized Sporlan BQ type TXV. Orifice if properly sized.

    Quote Originally Posted by mccool View Post
    Liquid line drier in case was partially plugged, S.G. was cut in before drier??

    What are the components in each case?
    Suction line solenoid with 90 degree EPR for MT operation?
    Forgot to add that Tech#1 replaced case drier. SG was installed after drier anyway.


    Quote Originally Posted by NANOTECH View Post
    CRO valve not set correctly or switchover solenoid not working properly
    Pressures taken at coil, upstream of DT solenoid/ORIT valve.

  9. #9
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,567
    Quote Originally Posted by air2spare View Post
    restriction in 1 or more distributor cap tubes?
    Even frost pattern on all tubes. Took the nozzle out and inspected. All clean and clear.


    Quote Originally Posted by I_bend_metal View Post
    Seeing as how I am a former resi guy and new to the refer tech gig, I'm
    going to take baby steps on this one....

    Am I correct in thinking that suction PSI is too low?

    (or do I need to head back to class?)


    Actually, the suction pressure is a wee bit high, but not terribly so. The case MFR calls for -22 degrees SST.

    Quote Originally Posted by dangpgt97 View Post
    I was thinking the same. Maybe the nozzle is plugged. Or possibly a plugged external equalizer line for the txv...
    I even replaced the external eq line to no effect.

  10. #10
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,567
    This was a tough problem.

    I had to bring in factory support and he made it so simple that I felt like an idiot.

  11. #11
    Join Date
    Feb 2006
    Location
    Phoenix,AZ
    Posts
    2,876
    Is the txv adjustable. If so. Open it up a few turns

  12. #12
    Join Date
    Sep 2006
    Location
    Chicago
    Posts
    474
    hmmmmmmmmmmmm. Is this an open air case where a heat duct or something could be disrupting the air curtain?

  13. #13
    Join Date
    Feb 2003
    Posts
    1,166
    Factory styrofoam peice at top behind discharge honeycomb was too big, (cut on wrong angle)blocking majority of airflow.
    Found this on several Hill end bunks at same store.
    Watts New, Ohm My, I been Electrically Commutated. Are U2.

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