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  1. #1
    Join Date
    Apr 2004
    Location
    Lombard, IL
    Posts
    29
    hello, guys I normally work on central airconditioner units but some one brought a refrigerator over and the compressor is kicking on and it is cooling but it only gets cool enough to keep food in it when it is on the coldest setting. The freezer part freezes water only if it is set on the coldest setting. I have a shrader valve to sweat in the suction line but I am not sure how to charge the system do I use superheat or subcooling?

  2. #2
    Join Date
    Dec 2002
    Posts
    174

    there...

    ...should be a metal label plate with model and serial number, sometimes it will give you correct charge amount in ounces

  3. #3
    Join Date
    May 2004
    Location
    Frederick, MD
    Posts
    1,003

    charging

    The simplest way I have found with any self-contained equipment (roof-top units etc) is to weigh the charge in. What I would do in your case is evacuate the system into a deep vacuum. Then, as was mentioned, go to the data plate and get the total charge for the unit. Be sure to see what refrigerant is needed in the piece of equipment you're working on. Weigh in the charge. If the problem persists, you now know it isnt the charge because you did the job right! Good luck.

  4. #4
    Join Date
    Mar 2003
    Posts
    373
    I have found a few units with no data as to oz. of charge required,
    if you watch your head pressure and sub-cooling... that will help you determine when you are getting close to enough, and then watch for frost on the suction line, most of these domestic cap tube systems, you will get down to temp and will see frost beginning to creep down the suction line, remove refrig until that clears, then your charge is very close to what it would have been on the name plate, alot of these units only have 10 oz., so you don't need much
    hem

  5. #5
    Join Date
    Oct 2001
    Posts
    2,101
    Originally posted by ice_cube_30
    hello, guys I normally work on central airconditioner units but some one brought a refrigerator over and the compressor is kicking on and it is cooling but it only gets cool enough to keep food in it when it is on the coldest setting. The freezer part freezes water only if it is set on the coldest setting. I have a shrader valve to sweat in the suction line but I am not sure how to charge the system do I use superheat or subcooling?


    Before you start installing access valve, make sure that this fridge really needs refrigerant.
    Make sure that condenser coil is clean and fan is running.
    Make sure that evap. fan is running.
    Check if shroud in the back is in good shape and not letting air bypass condenser.
    Manually advance defrost timer and let it go through the cycle.
    Check amp draw to make sure that defr. heater and defrost thermostat are working
    good. If cold control cycles compressor on and off before freezer reaches right temperature, then this is possible problem.

    [Edited by sigma on 06-05-2004 at 02:45 PM]

  6. #6
    If you are sure all else is ok, add a valve, suck out the old stuff, charge with 409-A, liquid, go sllllloooooowww with it, get suction to about 12psi max, stop and see what goes overnight.
    Hey cockroach, don't bug me! ©

    www.AskTheDiceman.com

    www.TheColdConspiracy.com

    www.Pennwood-HVAC.Com

    Bring Em Home....

  7. #7
    Join Date
    Mar 2004
    Location
    Windsor, ON Canada
    Posts
    168
    I agree with Sigma, if the system will pull down, you dont have a ref. problem. Replace the stat, its much cheaper and is likely your problem. Don't add R409a to a R12 system for no reason unless you want to say goodbye to your compressor in the coming months.

  8. #8
    Well, I suppose it could be anything, hard to say from here but I gotta tell ya, every old fridge and I mean old ones, I ever worked on had mainly 2 things wrong with it, bad compressor or a leak.
    Occasionaly a bad defrsot timer or fan motor, never the stat....but who the hell knows.
    Hey cockroach, don't bug me! ©

    www.AskTheDiceman.com

    www.TheColdConspiracy.com

    www.Pennwood-HVAC.Com

    Bring Em Home....

  9. #9
    Join Date
    Sep 2001
    Location
    East Stroudsburg, PA
    Posts
    13,215
    Originally posted by Diceman
    Well, I suppose it could be anything, hard to say from here but I gotta tell ya, every old fridge and I mean old ones, I ever worked on had mainly 2 things wrong with it, bad compressor or a leak.
    Occasionaly a bad defrsot timer or fan motor, never the stat....but who the hell knows.
    And with every one of these problems, it's usually cheaper to buy a new fridge, unless there is some sort of emotional attachment to it, like granny gave it you when you moved into your first apartment...

  10. #10
    Yep, go to Sears or homo depot, get a display or scratch & dent special.
    Hey cockroach, don't bug me! ©

    www.AskTheDiceman.com

    www.TheColdConspiracy.com

    www.Pennwood-HVAC.Com

    Bring Em Home....

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