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  1. #1
    Join Date
    Mar 2011
    Location
    Houston
    Posts
    77

    Cool charging a split system with 50 degree ambient

    Anybody have some good tricks. Can I still use superheat possibly at the evaporator?

  2. #2
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,758

  3. #3
    Join Date
    Apr 2007
    Location
    Philadelphia
    Posts
    2,192
    Block the condenser airflow to get the head up to where you would be on a warm summer day. the 50 ambient would be easy to account for, But it obviously must be cool inside with a low return temp and that would be the challenge IMHO.

  4. #4
    Join Date
    Oct 2010
    Location
    Utah
    Posts
    48
    Try charging using sub cooling.

  5. #5
    Join Date
    Aug 2008
    Posts
    91
    Recover, evacuate, weigh in the manufacture charge, and move on!

  6. #6
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,758
    Quote Originally Posted by Hardwater View Post
    Recover, evacuate, weigh in the manufacture charge, and move on!
    How does that compensate for lineset length?

    With that as an unknown, you cannot simply weigh in and go.

  7. #7
    Join Date
    Apr 2007
    Location
    Philadelphia
    Posts
    2,192
    I agree! Also if it is a larger split with a large charge, Why make the customer pay for all that nonsense of recovering and weighing? Charge it in, You should know how to if you are in thie field, hopefully. Most units have a charging chart you can get through the manuf. you need to get your return wetbulb etc. Or tell them you will be back in the spring, they are most likely not using it in 50 degress, And if they are it most likely has a low ambient kit.

  8. #8
    Join Date
    Feb 2010
    Location
    Landis North Carolina
    Posts
    528
    You can block airflow on condenser and use superheat calc to determine correct superheat unless its txv the do same thing only charge to subcool. Its in the book. Also if you have a heat pump to keep from lowering temp in space too much just energize 1 stage of srip heat to keep from dropping too low for charging. then switch to heat and determine if your spilts are acceptable for heating.(indoor and outdoor)

  9. #9
    Join Date
    Oct 2011
    Location
    Las Vegas, NV
    Posts
    525
    I have a switch set up that I temporarily wire into the condenser fan motor, and manually modulate the head pressure. unless there is a gas furnace to run to warm up the inside, then the cold inside temps still make it a pain to dial in. I always schedule to return when it's warm to double check the charge.

  10. #10
    Join Date
    Oct 2011
    Location
    hayward ca
    Posts
    58
    I have often wondered if one of those propane jet sounding heaters aimed at the right area would do the trick, havent gotten myself to trying it yet though.

  11. #11
    Join Date
    Oct 2011
    Location
    Las Vegas, NV
    Posts
    525
    I had to do a start up today on a a split system with a gas furnace. It was 57 degrees out, but I was fortunate enough to be able to start the heat up first and let the heat run for a while when I was evacuating, so I brought the inside temp up to 84. That made it easier when charging.

  12. #12
    Join Date
    Aug 2008
    Posts
    91
    Quote Originally Posted by jpsmith1cm View Post
    How does that compensate for lineset length?

    With that as an unknown, you cannot simply weigh in and go.
    Well,any tech worth his salt should know that you have to figure in the line set. If they don't know how to do it then maybe a little more of an education is in order!!

  13. #13
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,758

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