Results 1 to 9 of 9
  1. #1

    Walk-in freezer...in afghanistan

    I'm a brand new HVAC/R journeyman curently deployed. My knowledge base keeps me out of trouble but I am having issues and don't have any other A/C techs out here. With that said, here it goes:

    We have a unit that isn't cooling. Shocking. It's a small 150 cubic/ft portable walk-in refrigerator/freezer. I fixed a serious leak on the hot-gas solenoid gasket and weight the charge back in (8lbs, r-12). Suction line is only cold AFTER the crankcase regualtor valve, and the disharge line is hot coming right off the compressor, but not at the condeser. The sightglass slowly fills up and bubbles, so it lead me to think there is a restriction. My sneaky suspicion is the TXV isn't driving. I know this all sounds like a bit of a cluster**** but any help is appreciated.

  2. #2
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    24,947
    This unit got very warm?

    A CPR (crankcase pressure regulator) prevents the compressor from overloading in high load situations, so it may be doing its job.


    Let it run a while.

    What are the pressures on both sides of the CPR? What is the amperage of the compressor vs the nameplate amperage?

  3. #3
    Join Date
    Dec 2011
    Location
    New Zealand
    Posts
    1,983
    It is difficult when there is no one about to ask.
    so a little advice, refrigeration is all about temperatures, pressures and current. so draw a simple diagram of the system you are working on, and write the data next to each part. This will do 2 things "a" help you understand the system better (because you are thinking more about the system/drawing) and "b", it helps use help you because we can almost see what you are seeing.

  4. #4
    Join Date
    Mar 2013
    Location
    swan valley idaho
    Posts
    626
    what's the suction/discharge pressure, and superheat

  5. #5
    Join Date
    Jul 2012
    Location
    Western KY
    Posts
    1,221
    R12? I thought they were all gone from our inventory? Is this a MilSpec or a civilian machine?

  6. #6
    Join Date
    Nov 2007
    Location
    Tucson, AZ
    Posts
    89
    Tommy Knocker Pakistan still makes R-12 I spent 2 years in Afghanistan and 1 year in IRAQ.. We need info Super heat and subcooling. box temp and ambient.. Is it a txv! is the super heat high and discharge normal? give us something to work with.
    Bruce

  7. #7
    Join Date
    Jul 2005
    Location
    FLORIDA
    Posts
    1,163
    sequence of operation .......... cpr and fan controls have to put into perspective and know how they work together in a system operating at different times on certain systems .......... cpr acts like a hold back valve and stops compressor from overloading on start up and after defrost, fans should not run till coil temp and presure drop and then fans start and presure will rise again and now look at your charge glass should be full now super heat can be check when box is close to temp
    once you think you've seen it all
    (THINK AGAIN)
    I would rather work for free than be look upon as a thief!!!!!

  8. #8
    Join Date
    Sep 2012
    Location
    northern Ohio
    Posts
    95
    Quote Originally Posted by barbar View Post
    It is difficult when there is no one about to ask.
    so a little advice, refrigeration is all about temperatures, pressures and current. so draw a simple diagram of the system you are working on, and write the data next to each part. This will do 2 things "a" help you understand the system better (because you are thinking more about the system/drawing) and "b", it helps use help you because we can almost see what you are seeing.
    this is exactly how i started in this field in the late 70s, it is still the same today. draw pictures, fill in the blanks, and 9 out of ten times you will find your answer before you finish. i still find some of these cude drawings in control panels that hepled me way back when. sometimes it's interesting to compare "then and now", and see how changes have impacted these old systems. i still do the same thing now only not as often, or maybe not often enough. and thank you to "itry" for your service,

  9. #9
    Join Date
    Dec 2011
    Location
    New Zealand
    Posts
    1,983
    Quote Originally Posted by refrigeration johnny View Post
    this is exactly how i started in this field in the late 70s, it is still the same today. draw pictures, fill in the blanks, and 9 out of ten times you will find your answer before you finish. i still find some of these cude drawings in control panels that hepled me way back when. sometimes it's interesting to compare "then and now", and see how changes have impacted these old systems. i still do the same thing now only not as often, or maybe not often enough. and thank you to "itry" for your service,
    After 30+ odd years, I still do it, sometimes helps just to slow me down, "less speed, more haste"

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event