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  1. #1
    Join Date
    Feb 2005
    Posts
    147
    Hey ya'll. Ive been in the industry for 7 years nows but I wanted to ask a randon question. I just passed my my NATE exam in heat pumps and we were discussin chargin methods. The question is, how do all of you, (check and charge) a heat pump. Lets say it's 35 degrees outside and we have a R-410A and then a R-22 system. How would you check and charge both of them. Just curious! I like hearing from other people. Thanks


  2. #2
    Join Date
    Oct 2002
    Posts
    369
    The easiest method is to weigh in the charge....otherwise follow the manufacturers pressure/temperature charts....or the superheat or subcooling method.
    Havin'a good time is what life is all about.

  3. #3
    Join Date
    Sep 2001
    Location
    Vancouver Canada
    Posts
    996
    Best way is to weigh in the charge at those temps. Charging is always more accurate in cooling mode. You can usually come pretty close in the heating mode then come back in warm weather and check it again. Follow manufacturers recommendations for winter charging, every unit will have charging instructions somewhere, either inside the door or in the installation manual.
    "Go big or Go Home"

  4. #4
    Join Date
    Apr 2004
    Posts
    7,680
    The problem in charging in cold weather is a matter of where the refrigerant is stacking, if there is an accumulator, charging by pressures and temps can become inaccurate beecause there is no way of telling how much refrigerant is stacked in that accumulator.

    At 35 degrees, charging must be done by weight, however in many cases a charge "check" can be performed to verify the charge provided airflow is verified and coil surfaces are clean and frost free.

  5. #5
    Join Date
    Aug 2011
    Posts
    1,257

    weight in charge in winter

    i have read a lots good information here about charging heat pump in heat mode,i guess i have to weight it in for now ,i try different way to do it,include hot gas method,and add if is to hot,recover if is to cold(vaper line temp),none of them work well,will be great if any tech out there have better way to charge it without recover and recharge,thanks,

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