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  1. #14
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    Quote Originally Posted by ryan1088 View Post
    4 pounds per horsepower??!? I have ever heard that. What if......it has a headmaster? What if it doesn't? Big difference in charge there....
    Thats what the 1 tech guy from Coldzone told me, I hope he wasn't a retard
    America; first we fight for our freedom,
    then we make laws to take it away.

    -Alfred E Newman

  2. #15
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    Jul 2012
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    Western KY
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    Quote Originally Posted by jpsmith1cm View Post
    The amount of refrigerant in the receiver is largely immaterial for an operating system other than that a liquid seal is maintained at the receiver outlet at all times.

    Larger, built up systems can have miles of hidden piping, making it impossible to compute the charge by measuring the lines and also impossible to pump the entire system down for servicing.

    The biggest priority is to maintain temperature. The best way to do that is to ensure that quality liquid is delivered to the TEV at all times.

    Limiting yourself to the receiver's capacity as determined by the method you describe isn't going to work in all cases.

    Example. I'm commissioning systems today. The listed receiver capacity of one system at 80% is 702#. The system contains 1350# of R-22 with a 20-25% running receiver level. By your logic, I should remove almost half of the system's charge. That would result in a quarter of a grocery store not maintaining proper product temperatures.
    I don't think he has a whole store rack here. Sounds like a couple walk ins. Excellent info you have provided but maybe a bit above this thread. A simple WI with a couple fan coils receiver capacity method most efficient for initial charging IMO.

  3. #16
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    Quote Originally Posted by Tommy knocker View Post
    I don't think he has a whole store rack here. Sounds like a couple walk ins. Excellent info you have provided but maybe a bit above this thread. A simple WI with a couple fan coils receiver capacity method most efficient for initial charging IMO.
    It is a couple of walk ins. albeit large ones. I do appreciate that info as well, I hope to get into the really large stuff soon
    America; first we fight for our freedom,
    then we make laws to take it away.

    -Alfred E Newman

  4. #17
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    Sep 2008
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    Western PA
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    Quote Originally Posted by ryan1088 View Post
    4 pounds per horsepower??!? I have ever heard that. What if......it has a headmaster? What if it doesn't? Big difference in charge there....
    I agree.

    Tech guy might need a lesson.

  5. #18
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    Sep 2008
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    Western PA
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    Quote Originally Posted by Tommy knocker View Post
    I don't think he has a whole store rack here. Sounds like a couple walk ins. Excellent info you have provided but maybe a bit above this thread. A simple WI with a couple fan coils receiver capacity method most efficient for initial charging IMO.

    Whole rack or a couple of walk-ins.

    It doesn't matter.

    Charging by receiver capacity is a nice start, but if you aren't delivering quality liquid to the TEV, you aren't keeping temp, and you may not be able to pump it down into itself. Fact of life.

    I used those racks as an example, but I can find others where charging to receiver capacity would severely undercharge the unit without going to a full rack system.

  6. #19
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    Quote Originally Posted by jpsmith1cm View Post
    I agree.

    Tech guy might need a lesson.
    I certainly hope not... The job is 3 hours away and that service call would really suck. Box got down to temp just fine, everything seemed to be going great.
    America; first we fight for our freedom,
    then we make laws to take it away.

    -Alfred E Newman

  7. #20
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    Feb 2006
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    Phoenix,AZ
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    How do you calculate the new micro channel coils additional charge with Head master?

  8. #21
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    Western PA
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    Quote Originally Posted by KB Cool View Post
    How do you calculate the new micro channel coils additional charge with Head master?
    Good question.

    I think that there was a thread on this a while back and it comes down to a factory calculated amount.

    Check the manual.

  9. #22
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    Quote Originally Posted by LibertyTree View Post
    I certainly hope not... The job is 3 hours away and that service call would really suck. Box got down to temp just fine, everything seemed to be going great.
    4# per compressor horsepower is a rule of thumb. Just like "beer can cold"

    It might work, but it isn't correct.

  10. #23
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    Quote Originally Posted by jpsmith1cm View Post
    4# per compressor horsepower is a rule of thumb. Just like "beer can cold"

    It might work, but it isn't correct.
    You've forgotten it's beer can cold and 30 degrees above ambient temperature.

  11. #24
    Join Date
    Jul 2000
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    Guayaquil EC
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    10,260
    Quote Originally Posted by jpsmith1cm View Post
    Good question.

    I think that there was a thread on this a while back and it comes down to a factory calculated amount.

    Check the manual.
    New Heatcraft units with the new HyperCore microchannel condensers still don't come with detailed info on the required flooding charge (AKA, winter charge). The only thing I've seen in writing about this HyperCore Q&A (See Question #12):

    Heatcraft HyperCore Q&A

    When I'm doing an installation of a typical air-cooled unit and need to get a rough idea of how much refrigerant I'll need on hand (not necessarily the exact charge), I've use the following method:

    1. Condensing Unit Operating Charge (Normal Ambient) - For this I typically will use 20% of the receiver capacity, which will be found either in the manufacturer's I&) manual or the sales catalog data.
    2. Flooding Charge - The flooding charge can be calculated by using the Sporlan method or with the manufacturer's published winter charging data.
    3. Evaporator Operating Charge - Many manufacturers don't publish the evaporator operating charges any longer, but for the standard, low profile evaporators I use a rule-of-thumb of 2 lbs per fan...ie, a 4 fan unit would account for about 8 lbs of refrigerant. To get a better estimate or for different style evaporators, call the manufacturer for the proper operating charge. *
    4. Liquid Line Charge - Use the total lineal footage of the liquid line and determine the amount of liquid by using the manufacturer's I&O manual, which usually has charts for this. There's really no need to calculate the suction line.


    Add these up and you'll have a good estimate of what the system will need. For the actual charging, use the cleared sightglass plus the winter charge method described earlier.

    * The average walk-in evaporator doesn't have a huge operating charge, but other types of systems may surprise you. As an example, if you''re installing a 48 ft lineup of service deli cases, they might have a combined operating charge of over 40 lbs. and its 3 HP condensing may only have a 12 lb receiver.

  12. #25
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    Jun 2011
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    Seattle WA
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    Quote Originally Posted by jpsmith1cm View Post
    4# per compressor horsepower is a rule of thumb. Just like "beer can cold"

    It might work, but it isn't correct.
    Its pretty sad when the main service guy for Coldzone tells me this...
    America; first we fight for our freedom,
    then we make laws to take it away.

    -Alfred E Newman

  13. #26
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    Mar 2009
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    Mid-Mo
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    You're lucky then you didn't get their worst.....haha!

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