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  1. #1
    Join Date
    Feb 2007
    Posts
    2

    r502 low temp replacement

    93, 6hp low temp discuss was running on 502,
    any sugestions?

  2. #2
    Join Date
    Feb 2007
    Location
    Texas
    Posts
    40
    A good replacement R-404a . Change the oil to POE

  3. #3
    Join Date
    Dec 2005
    Location
    Memphis, TN.
    Posts
    823
    Why not R-408?

    CM
    "I don't care what you could get it off the net for, they wont warranty it and neither will I"!

    And if you don't like my "flat rate up front pricing" try and negotiate the price on that big mac you just bought pricing is exactly the same method!

  4. #4
    Well, You have these choices: www.refrigerants.dupont.com to work with. ISCEON MO79 oil- MO,AB,POE or Suva R-404A oil- POE , Suva R-408A oil-AB,MO, Suva R-507, oil-POE Suva HP-80 oil-AB,MO. Have a Suva day.
    FEN

  5. #5
    Join Date
    Feb 2007
    Location
    Texas
    Posts
    40
    I agree R-408 is a great replacement as well. Just look at price of the gas and what you see more of........It's tough to have a Baskin Robins in your truck "31 flavors" just a thought.

  6. #6
    Join Date
    Jan 2006
    Location
    Near Atlanta, GA.
    Posts
    14,531
    R-408 is probably the easiest replacement. The manufacturer says it's OK with mineral oil, but I still think it's best to change part of it out with AB. Or...you could do a complete oil change to POE, which works well with 408, and down the road a ways you could do one more oil change and you'd be good for 404.

    HP-80 is also a fine replacement for 502 low temp, use AB oil for that one.

    The best long term solution might be 404. Go with all POE oil, you might need to change it twice to get the original oil content down below the recommended 5%. Change the dryer and pull a hard vacuum. POE has a tendency to dissolve all the built up crud in the system so I'd plan on going back in a day or two and changing the dryers again.

    With either refrigerant, check the superheat when near temp. None of the replacement refrigerants are actual drop ins so you'll likely need to make some minor adjustments. Typically with 408 the TXV will need to be closed off a bit.

    Edited to fix my screw ups...
    Last edited by k-fridge; 02-23-2007 at 02:07 PM.

  7. #7
    Join Date
    Dec 2003
    Location
    Location!, Location!
    Posts
    929
    We had a tandem system with 7.5 hp pumps that had compressor failures at 2 different times, so we were retrofitting with a -10F evaporator(couldn't shut down whole unit). We chose HP-80 and zerol 200TD oil, and one was done in 1993 and the other done in 1995, with absolutely no troubles as of today. Box is a 40' X 15' X 7' meat storage.

  8. #8
    Join Date
    Dec 2005
    Posts
    1,918
    if you are to conver the freon of the system that has mineral oil, try to use AB oil. It is more forgiven then POE oil.

    Yes, it is true that 404A and 134a are the long term freon. But

    If the system uses mineral oil, it is old and near the end of its life. Don't put any more stress on the machine and especially more headache on you.

  9. #9
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,371
    Quote Originally Posted by k_fridge View Post
    ....Or...you could do a complete oil change to POE, which works well with 409...
    I think you meant to say 408.

    MP-39 is also a fine replacement for 502 low temp, use AB oil for that one.
    That should be MP-80 (R402A).

    Bad day, Ken?

  10. #10
    Join Date
    Jan 2006
    Location
    Near Atlanta, GA.
    Posts
    14,531
    Quote Originally Posted by icemeister View Post
    I think you meant to say 408.

    That should be MP-80 (R402A).

    Bad day, Ken?
    Jeez, that's what I get for posting in a rush. Thanks for catching me on those.

  11. #11
    Join Date
    Oct 2001
    Location
    Stoney Creek, Ontario
    Posts
    884
    i wouldnt recommend HP80 as a replacement, - to many high head calls in summer, used HP80 in early 90's , now always use 404 or 507

  12. #12
    Join Date
    May 2004
    Posts
    1,865
    ISCEON MO79 (422A) is the best long term 502 replacement. No need to change to POE oil like with some of the others. We have a couple racks running this stuff for over a year with no problems.

  13. #13
    Quote Originally Posted by ace12 View Post
    ISCEON MO79 (422A) is the best long term 502 replacement. No need to change to POE oil like with some of the others. We have a couple racks running this stuff for over a year with no problems.
    And thats why I posted at the beginning of choices.
    FEN

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