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  1. #1
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    107

    Need help On walk in cooler

    I got a call: a walk in cooler not cooling.it is a 2 hp water cool condensing unit with a liquid receiver and 2 tons indoor coil,the tev is danfoss tx2 model and the orifice is #4, R22 system.
    The coil was build up with ice when I got there.After the ice melt and start the unit. The hi side pressure is 170 psi and low side pressure is 28psi. The outlet water temp is 75f and inlet temp is 47f. Adjust the water regulater and set the outlet temp to 90f. The pressure go to 200 psi and 30 psi, the super heat is 50f and the sc is 16f. Ice start to form again. Checked fans and comp,volt is 116v and 230v, 0.5 amps for each fan and 4.6 amps for comp.Check filter drier,side glass,no restriction.replaced the orifice for the tev. It had the same problem. Top up with 9 oz r22, the suction pressure up to 33psi and liquid line pressure is 225psi. The super heat is 48f and the sc is 46f. And the liquid line became cold. Hold the bulb of the tev, the suction pressure went up to 36 psi, Is the tev not good and why the sub cooling went up and liquid line became cold? Thanks .

  2. #2
    Join Date
    Apr 2001
    Location
    Over Here
    Posts
    1,105
    The SH is high. The TXV needs adjusting to decrease the SH. Where are you reading your suction temp? At compressor, or evaporator outlet?

    SC @ 16 is a little high also. Is the SC after your work really at 46 or is that a typo?

    What is the box temp with these readings?

  3. #3
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    107
    yes, I had adjusted the tev, if I turn the other way, the suction pressure will go even lower.the suction pressure i measured at the out let of the coil. the sc is 46f, i measured at the outlet of the reciever and the temp i got it from the outlet of the condenser.

  4. #4
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    107
    the box temp was at 60 f and it had high humidity inside.

  5. #5
    Join Date
    Apr 2001
    Location
    Over Here
    Posts
    1,105
    You definitely have flow problems. If valve adjustment isn't working, then it's time to replace the valve.

    Keep in mind when adjusting txv superheat, you are looking more for temperature response than pressure, albeit your low pressure here is way too low for a 60 degree box.

  6. #6
    Join Date
    Jul 2010
    Location
    So-Cal
    Posts
    580
    Is your sight glass full?
    Evap coil clean?

  7. #7
    Join Date
    Apr 2005
    Location
    where the beer flows like wine
    Posts
    2,871
    sounds like the TXV is bad,the Danfoss made in china are notorious for failing that way, replace it with a Sporlan.

  8. #8
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    107
    Quote Originally Posted by jackintheboxtec View Post
    Is your sight glass full?
    Evap coil clean?
    yes,the coil is clean and the sight glass is full.

  9. #9
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    107
    Quote Originally Posted by thermojohn View Post
    You definitely have flow problems. If valve adjustment isn't working, then it's time to replace the valve.

    Keep in mind when adjusting txv superheat, you are looking more for temperature response than pressure, albeit your low pressure here is way too low for a 60 degree box.
    I agree with that. When I adjusted the txv, I checked the temp change at the suction line. Its super heat value getting even higher.

  10. #10
    Join Date
    Mar 2004
    Location
    Las Vegas, Nevada
    Posts
    1,647
    Think I gotta go with Jack on this one. Are you SURE you're not leaking somewhere?
    The views and opinions posted here are my own. They do not reflect the corporate policies of my employer and will most likely get me fired at some point.

  11. #11
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    107
    Quote Originally Posted by engineerdave View Post
    Think I gotta go with Jack on this one. Are you SURE you're not leaking somewhere?
    Checked all joints with liquid detector and its clear. Vaccume the system and it hold for more than one hour. So far,....yes.

  12. #12
    Join Date
    Feb 2004
    Location
    Western New York
    Posts
    1,049
    Quote Originally Posted by markvilleman View Post
    And the liquid line became cold. .
    Tell us more about that... how cold, frosting after the drier?
    Experience is what you have an hour after you need it.

  13. #13
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,687
    I wouldn't worry a whole lot about subcooling on this system. Particularly not as a measure of charge.

    Get the sightglass clear and call it good.

    I would agree that you aren't moving the refrigerant that you need to. Cannot confirm TEV or Drier, but you are on the right track.

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