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  1. #1
    Join Date
    Oct 2010
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    Anderson, South Carolina, United States
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    AK900 pt conversion 421a

    I'm charging a dry 22 unit with 421a and noticed the pt conversion on my ak900 for 421a is 10* different between the high and low. Can somebody check their 421a setting to see if its just mine or is it just loaded to the guage wrong.
    Heating/Cooling Services Inc.
    www.andersonhvacservice.com

  2. #2
    Join Date
    Mar 2007
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    wedged in freezer shelf
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    I tried to find the "temperature glide" for the blend and couldn't find it.
    I did read they are putting a lubricant in the can ....... Yikes

  3. #3
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    Sep 2007
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    NH
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    Must be the glide.

  4. #4
    Join Date
    Oct 2010
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    Anderson, South Carolina, United States
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    At 0psig on high and low the sat temp reading was 10* different on the ak900s. We've used it a few times and its worked well so far.

  5. #5
    Join Date
    Jul 2009
    Location
    Kansas
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    372
    Does look like a ten degree glide: http://www.certifiedrefrigerant.com/...rt%20r421a.pdf

    Are the compressors your using POE? Retrofit sheets say that it's compatible with Mineral Oil. But it's a mixture of 58.0% R125 and 42.0% R134a which are both not miscible with Mineral Oil: http://www.certifiedrefrigerant.com/...rt%20r421a.pdf

    Food for thought...

  6. #6
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    wedged in freezer shelf
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    My 1250 is showing about 10 at 0 and moves closer like 6 over 100

  7. #7
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    Oct 2010
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    Anderson, South Carolina, United States
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    Quote Originally Posted by itsiceman View Post
    My 1250 is showing about 10 at 0 and moves closer like 6 over 100
    Why is it like that, I don't care what the glide is 0 psig and 0 psig should be the same saturated temp??? Not that I don't care what the glide is, in just sayin the temps should be the same at a given pressure.

  8. #8
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    Sep 2007
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    NH
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    Nope

  9. #9
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    Sep 2007
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    NH
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    The gauges use dew point and bubble point.

  10. #10
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    Quote Originally Posted by jtrammel View Post
    Why is it like that, I don't care what the glide is 0 psig and 0 psig should be the same saturated temp??? Not that I don't care what the glide is, in just sayin the temps should be the same at a given pressure.
    Some charts you are used to seeing will divide dew and bubble points into
    a single line and cross over at some point.
    At one pressure there is a dew and bubble point with blends.

  11. #11
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    NH
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  12. #12
    Join Date
    Jul 2009
    Location
    Kansas
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    That's the thing with temp glide. Its gonna be different for your low side and high side at the same pressure. Bubble Point on high side and Dew Point on low side.

  13. #13
    Join Date
    Oct 2010
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    Anderson, South Carolina, United States
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    I just read all about it, thanks for the clarification. I've never worked with any refers that were that different between the dew, bubble, saturated temps. It just threw me for a loop when they were different on the guages. I understand it much better now. Gonna take some getting used to dialing in a charge.

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