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  1. #14
    Join Date
    Jan 2012
    Location
    Tallahassee,Fl
    Posts
    144
    Yes I believe it is cracked you need to check the super sweet how cute is that a liter oil...


    lol...

  2. #15

    Help if how to download when you living in Asian Country. Also not allow to Check-out

    Quote Originally Posted by rdholder View Post
    You can download this book it has a superheat chart, its FREE

    http://shop.rdholder.com/Troubleshoo...leshooting.htm

    FREE articles on Superheat, Subcooling and A/C Troubleshooting. For the FREE downloading of the articles go to Book and Papers on HVAC on the main page, put them in to the cart then, you must click on the PRINT AND CALL button for payment at check out. This method allows me to process your downloading at NO CHARGE.
    Hi,
    Help if how to download when you living in Asian Country. Also not allow to Check-out using Paypal.
    Many Thanks,
    Rodel

  3. #16
    Join Date
    Jul 2012
    Location
    CT
    Posts
    204
    What we do when the name plate doesn't have any of the charging info we use HVAC buddy. You type in the system information and it tells you what it should be for subcool or superheat. Its not the best thing but when you don't have any manufacturer specs on subcooling or superheat it definitely gets you into the ball park.

  4. #17
    Join Date
    Nov 2013
    Location
    Dunedin fl
    Posts
    75
    You would think the manufacturers would provide that info on their web sites

  5. #18
    Join Date
    Apr 2012
    Location
    Texas
    Posts
    184
    You must have enough subcooling to offset the pressure drop of the liquid line, plus a couple of degrees as a buffer, or the system will not work correctly.
    A solid column of liquid at the expansion device.
    Economy - Quality - Speed <---- pick two

  6. #19
    Join Date
    Dec 2002
    Location
    in a house, Appomattox, Va.
    Posts
    3,255
    Due to the higher effs/ smaller evap coils volumes, systems are getting a lot more touchy about charge.

    They'll work fine in cooling, them the head pressure goes crazy in ht mode. much less forgiving on some. One of Lennox guys said can be little as 10 oz on charge can throw off.
    Col 3:23


    questions asked, answers received, ignorance abated

  7. #20
    Join Date
    Dec 2006
    Location
    Goodyear, AZ
    Posts
    197
    All way use manufacturer specs on subcooling or superheat if you have them but if not.

    for Superheat:

    Always check for proper evaporator air flow when charging a fixed orifices superheat, be sure to use the charts that each manufacturer’s can supplies for the system that is being charged or a formula for fixed orifice is.

    {((3xindoor wet bulb)-outside dry bulb)-80}/2

    An A/C with a Thermostatic Expansion Valve (TXV) is charged to the subcooling of the liquid line leaving the condenser because the superheat is fixed by the TXV. The superheat is specified by manufacturer and is normal between 16 degrees +- 2ΊF in most residential air conditioning systems. Subcooling is the amount of liquid held back in the condenser. This allows the liquid to give up more heat, below saturated pressure- temperature. For every one degree of subcooling at the same condensing+ pressure, capacity will increase .5 percent. See the chart that I developed for HVACPro app. The subcooling will change at 96 degrees out side and 52 degrees wet bulb inside from 14.5 to 4.5 when the wet bulb inside is 88 degrees. Increasing subcooling with an increase of discharge pressure and compression ratio, decrease capacity. Add 5 degrees of subcooling for every 30 feet of liquid line lift to prevent the formation of bubbles, flash gas due to the pressure drop.

  8. #21
    Join Date
    Dec 2006
    Location
    Goodyear, AZ
    Posts
    197
    Look at my profile for my e-mail and I will send it to you

    Roger

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