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  1. #14
    Join Date
    Nov 2019
    Location
    Wyoming
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    76
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    Thread Starter
    Hang on let me get the tape off my mouth. OK, so Ive heard and read in the books about charging by sub cooling. I have not actually done it yet.So, next summer will be a first. And I figured out, I probally over charged my first couple units. I am not super technical when reciting what ive done.So, I charged the units to 48F not 50 Because I started reading all sorts of peoples ideas on r410a. Now, my books say 118 to 120 psig on the low side and to charge by liquid into the liquid line.But then you hear about charging to 45F and even 48F, I am reading now that these are for dessert applications. So I figure where I am at I should just stick to the books and go with 118 psig. I am starting to understand the airflow importance and incorporate the subcooling method. I started with charging only r22 and so subcooling was not really discussed. And now I read that I need to charge r410a upside down and barely cracked to vaporize into the suction side. What?!! whats wrong with liquid into the liquid side?

  2. #15
    Join Date
    Jun 2014
    Location
    Dover, DE
    Posts
    11,682
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    There is no such thing as charging to a certain pressure.
    Refrigerant is volatile when it comes to changing in load and temperature. A certain pressure doesn’t mean anything is working right or not.
    R-410A is a blend with a small glide. It should always be charged via a liquid.
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

    Local 486 Instructor & Service Technician

  3. #16
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    42,433
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    Refrigerant changes pressure as the temperature goes up or down... that is why we have this thing called a 'P/T' chart (pressure/temperature)... might want to study that...
    (Yeah... that may be too much tech information in a public forum... sorry)

    You REALLY, REALLY need to get your PRO rating...
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  4. #17
    Join Date
    Nov 2019
    Location
    Wyoming
    Posts
    76
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    Thread Starter
    9 Posts away. OK it is sounding like you have to use a multiple of things and not just one when charging. I understand the concept of each such as PT chart , low and high side pressures and evaporation temps, sub cooling,Delta T, Liquid Charging by weight and scale. I am hoping to simplify this in my head but it is a bit much. R22 appeared to be much easier to charge or maybe it was because I wasn't seeing the whole picture.

  5. #18
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    25,680
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    They all operate under the same Thermo dynamic principals

  6. #19
    Join Date
    Aug 2009
    Location
    Maine
    Posts
    8,146
    Post Likes
    Quote Originally Posted by pecmsg View Post
    so your going to purchase a compressor now and let the warranty possibly run out?

    My supply houses keep many in stock, and I can get one in a day or 2.

    Why compressors? Everything else fails much sooner, if your going thru compressors you might want to find out why!
    No find out why. This guy loves to sell compressors. There are times when I wished I had a 4440 on the truck, but I can usually have one in an hour.

  7. #20
    Join Date
    Jan 2004
    Location
    PA
    Posts
    78,337
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    Residual R22? Not if you pulled a good vacuum.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  8. #21
    Join Date
    Mar 2015
    Location
    Tx
    Posts
    1,354
    Post Likes
    Quote Originally Posted by AlexCollins View Post
    Hang on let me get the tape off my mouth. OK, so Ive heard and read in the books about charging by sub cooling. I have not actually done it yet.So, next summer will be a first. And I figured out, I probally over charged my first couple units. I am not super technical when reciting what ive done.So, I charged the units to 48F not 50 Because I started reading all sorts of peoples ideas on r410a. Now, my books say 118 to 120 psig on the low side and to charge by liquid into the liquid line.But then you hear about charging to 45F and even 48F, I am reading now that these are for dessert applications. So I figure where I am at I should just stick to the books and go with 118 psig. I am starting to understand the airflow importance and incorporate the subcooling method. I started with charging only r22 and so subcooling was not really discussed. And now I read that I need to charge r410a upside down and barely cracked to vaporize into the suction side. What?!! whats wrong with liquid into the liquid side?
    You need to go back & reread your study book. Then hire a service tech .

  9. #22
    Join Date
    Jan 2010
    Posts
    18,060
    Post Likes
    Quote Originally Posted by AlexCollins View Post
    What?!! whats wrong with liquid into the liquid side?
    Well for one thing the system pressure will most likely be higher than your refrigerant cylinder pressure.
    Now if you're talking about changing a system that's been pulled into a vacuum, that's entirely different.

  10. #23
    Join Date
    Sep 2018
    Location
    Summerville SC
    Posts
    41
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    You can’t just convert any r22 split system into a 410 with a condenser changeout and some magic flush. The flush is to get the mineral oil and any contaminants out. Not for the refrigerant.
    If they are heat pumps, then you can’t do it, period.
    If have done a couple conversions on commercial splits , flush and change txv to 410. But cooling use only on a heat pump rated coil . They are rated at 400 psi.

  11. #24
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    32,059
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    If this seems a little disjointed to you, Alex, it is because this is an open forum. We are not going to provide steps in the open forums, because they get indexed by search engines.

    Unless your cooling season is right around the corner, do NOT buy any compressors right now, unless the system in question needs one, and then go ahead.

    Do not flush.

    Do not worry about oil.

    Do not worry about old 22 still in there.

    Learn how to draw a good vacuum, and use a good quality micron gauge.

    If the system tests positive for acid, there are remediation procedures.

    Post your questions in the Pro Residential forum once you get approved.

    Take part in some other threads, get to 15 posts, and use the link in the bottom of this post, "how to become a professional member."


    HTH
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    RSES CMS, HVAC Electrical Specialist
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  12. #25
    Join Date
    Feb 2004
    Location
    tenn
    Posts
    321
    Post Likes
    i always used a prestons guide when i could not get oem compressor i dont think they still publish it though
    birdman

  13. #26
    Join Date
    Jan 2004
    Location
    PA
    Posts
    78,337
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