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  1. #1
    Join Date
    Sep 2011
    Location
    Jax, Florida
    Posts
    22

    Factory Charge Weigh-In

    I would have been starting my career today (rained out) handling new units with a factory charge. We are installing 50 Goodman units at an apartment complex. My assignment was supposed to be handling the charging of the units. My foreman was going to go over some stuff with me before setting me out on this task, but since I am off today I figured I would ask here to see if there is any tips you guys can give me. I know there is a calculation based on line length etc, but not sure if there is anything else I need to watch out for or if its pretty standard charging stuff. Thanks.

  2. #2
    Join Date
    Mar 2011
    Location
    Galveston Texas
    Posts
    530
    the install manuals usually have the charging formula if the line length is long.

  3. #3
    Join Date
    Feb 2009
    Location
    Tallahassee, FL
    Posts
    6,051
    What kind of indoor units did you use? That will be a consideration. Also was the correct piston installed in the indoor? As well as lineset size used

    Goodman says that charge is good for 15ft only - in my experience it is good to more like 25-30?

    If outdoor units have smartcoil 5mm coil the charge is sensitive.

    Also manuals have recommendations to upgrade several parts if lines are over 75ft.

  4. #4
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,608
    Personally I don't trust that the factory got the initial charge right. I would prefer to check it using superheat or subcool (depends upon meter) on a warm day.

  5. #5
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
    Posts
    110
    If you got a fix bore inside,check the super heat when it's at temp,if u got txv inside,check the sub cooling.

  6. #6
    Join Date
    Jul 2010
    Posts
    19
    Quote Originally Posted by BaldLoonie View Post
    Personally I don't trust that the factory got the initial charge right. I would prefer to check it using superheat or subcool (depends upon meter) on a warm day.
    Spot on. Everyone should assume the factory charge is not right. It makes you a better tech, and you will understand more by going through this process.

    Gauges, clamp probe, length on lines, coil size, line set size, piston size, air flow testing should all be a part of a basic check for you on all these units. This is a perfect time to really understand how to service an A/C unit. Do it right and you'll thank yourself .

    Dale

  7. #7
    Join Date
    Aug 2008
    Location
    Eagle (Boise), Idaho
    Posts
    385
    And if all 50 are Goodman's, 5-10 of them will have to be replaced after you find a leak.
    Tell Obama he can keep the change

  8. #8
    Join Date
    Jan 2010
    Location
    Heat Pump Belt
    Posts
    92
    I agree SH & SC is key ive charge plenty of units using factory weight but my opioin it just gets you there once your there its time to fine tune that sucka

  9. #9
    Join Date
    Dec 2011
    Location
    bedford ind
    Posts
    1,092
    sh & sc are key, but what happens when the duct work is way off. I have replaced units with supply and return plenums so big I could crawl inside them on a 4 ton unit. The duct board had huge water drops all down the supply. Customer doesn't want the duct replaced, just the equipment. I know guys that figure their returns anywhere from .1 to over .05. Its' hard to get things right when the duct is all wrong.

  10. #10
    Join Date
    Jun 2007
    Location
    Greenwood Indiana (Indianapolis)
    Posts
    420

    Hmm

    my 1st thought was "are you refrigerant certified"

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