Results 1 to 4 of 4
  1. #1
    Join Date
    Jul 2004
    Location
    NJ
    Posts
    1,793
    Hi fellows,if you have time check my diagnosis.
    yesterday I checked a counter type refrigerator for a friend of mine who does AC work and is trying to improve on refrigeration.So I wasn`t in a rush and I tried to analize what caused what.
    The unit had two gravity type evaporators,that had some ice/snow on them.I defrosted the ice..
    I am not gonna remember every number now but simply had very high head,low back,hot comp.,high amp draw,not full sight glass.an LPC thats not cutting out,and was set low.
    cleaned the cond.coil,head pressure dropped. sight glass still not full,low side same.tried to charge R22,head goes up ,back doesn`t change much.amp draw increases,sight glass is not filling.filter drier doesn`t show any temp.diff.accross it,and yanked at it to see any move,nothing.suspected air in condensor,took the gas out,pulled vacuum,recharged doesn`t change the situation.expansion valve`s bulb was mounted on 12 o`clock,cap tube on the bottom(charging port on top) and not insulated..for some reason although having noticed this first,I left checking the expansion valve to the end. pumped down system, checked the strainer of exp.valve,cracked the king valve to see liquid line not restricted by filter drier,put everything back pulled the air out of the pipes,turned the bulb around,valve opens,and opens even more as I grab it.low side pressure is where its supposed to be for a warm box but now compressor can`t handle the even higher amp draw ,overload opens,and with the correct mounting of the bulb compressor can`t run long.opened the cover of the compressor terminals to see fried wires,insulation just crumbles.I started lecturing my friend saying:
    exp.valve starved the evap.thus high superheat cooked the compressor.somebody set the LPC cut out low to get some cooling,than tried to take care of frost by putting a clock.
    compressor was cooked, maybe had turn to turn short ,so when I allowed the normal suction pressure to it the load was too much for it.need new cond.unit,new exp.valve,new LPC,filter drier basicly everything.also get rid of the clock.
    how close do you think I got to the reality?
    I diagnosed or bull****ted?

  2. #2
    Join Date
    May 2004
    Posts
    11,999
    Who made the box? How old is the box?

    What is the size of your suction line? Is it horizontal or vertical where the TXV bulb is mounted?

    Is the LPC calibrated to your gauges?

    Did each evap coil have a TXV or one for two coils?

    How dirty was the condenser and is there good air circulation around it?

    My noise is picking up a strange odor


  3. #3
    Join Date
    Jul 2004
    Location
    NJ
    Posts
    1,793
    ?

  4. #4
    Altan, do a search here on this site for the posts made by Icemeister or CondensateDave () or Lmtd.
    You'll see they like to have a few specifics in front of them before they go answering questions.

    And usually, when we are exhorted to go look up the basics, we find the trouble BEFORE we come here online.

    Look up the type of questions they ask.

    And remember ... "inquiring minds want to know"

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