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  1. #1
    Join Date
    Jul 2019
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    Is mixing R409A with R134A OK?

    I just graduated from an HVAC school. My friend has a sandwich prep table that's not cooling enough so he called me to take a look at it. I went over there and look at the system, the system will run for about a min then shut off by the pressure switch. I figure the system is low on refrigerant. But the system has a tag says R409 from 2013. I told my friend I can't get any R409 right now and he has to call someone else to fix it.
    After the technician arrived, he put the gauge on and think the unit is low on refrigerant too. So he brings in a tank of R134A then charge it in the system. I was very confused. I ask him if he knows what was in the system. He told me it's ok to mix R409 and R134A.
    I'm wondering if he's right or wrong. And what will you guys do if a system was serviced but there is no tag and you don't know what's in the system. like R12 R134A R409
    Sorry for my writing. My grammar is very bad. Any answer will be greatly appreciated.

  2. #2
    Join Date
    Nov 2006
    Location
    Athens, Ohio
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    Mixing is wrong. The system now has an blended refrigerant with unknown properties. You should inform the owner his table has been incorrectly charged. The only way to correct it is to recover all the refrigerant and install a correct charge.
    AOP Rules: Rules For Equipment Owners.

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  3. #3
    Join Date
    Aug 2002
    Location
    Southold, NY
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    No you can not MIX refrigerants and unless the oil in that compressor is POE your friend WILL have problems down the road!
    Attached Images Attached Images

  4. #4
    Join Date
    Dec 2003
    Location
    Citrus County, Florida
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    anytime I change refrigerants I make sure to change the drier and shraders
    Doug

  5. #5
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    The only people that can mix refrigerants today are producers like Chemours or Arkema. Anything else is amateur hour.

    An on-site mixture cannot be recycled when recovered. You have to pay to get it destroyed.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

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  6. #6
    Join Date
    Jun 2014
    Location
    Dover, DE
    Posts
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    Unfortunately your friend will likely be responsible for paying the disposal fees for destroying that refrigerant blend. It cannot be reused or recycled.
    This can sometimes be very expensive.
    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

  7. #7
    Join Date
    Sep 2002
    Location
    Virginia
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    yank all that 409 out and put in 134 ... it works most of the time

    Make sure you can shine a flashlight thru the coil , if not , clean it , they get junk deep inside of them

  8. #8
    Join Date
    Dec 2009
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    maroon lazyboy
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    Well really now. How about finding the leak?

  9. #9
    Join Date
    Sep 2002
    Location
    Virginia
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    How can I get more beer money if I fix the leak ?? Dont be silly

  10. #10
    Join Date
    Dec 2009
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    maroon lazyboy
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    Quote Originally Posted by Snapperhead View Post
    How can I get more beer money if I fix the leak ?? Dont be silly
    Haha well I didnt say fix! Just nice to know where the gas is going.

  11. #11
    Join Date
    Jan 2010
    Posts
    18,580
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    Gas and go it don't get much easier
    The idea is not to fix the leak and each time you gas and go the mix gets stronger with the R134a. Eventually it's almost all R134a

  12. #12
    Join Date
    Sep 2002
    Location
    Virginia
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    Shhhhhhhhhhh .... this will be our little secret

  13. #13
    Join Date
    Dec 2009
    Location
    maroon lazyboy
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    Quote Originally Posted by VTP99 View Post
    Gas and go it don't get much easier
    The idea is not to fix the leak and each time you gas and go the mix gets stronger with the R134a. Eventually it's almost all R134a
    Yeah I was wondering how you would have to pay a recovery fee when its all gonna leak out anyway.
    Especially on a 1 lb system.

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