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Thread: R12 TO 404A

  1. #1
    CONVERTING 1/3 HP R12 TO 404A ,LOW TEMP W/ NEW 404A COMPRESOR ,SHOULD CAP TUBE BE CHANGED AS WELL AND HOW TO DETERMINE NEW CHARGE ,TAG IS MISSING FROM CONDENSOR THANX

  2. #2
    Join Date
    Feb 2004
    Location
    Medford Oregon
    Posts
    807
    Convering to R404A in your case only valid if you are changing the condesing unit. Converting an existing unit to another gas by only changing compressor will be quite a task. Your customer may not afford it, or at least may not pay you for the call backs. If you atr wealthy and want to do it, go ahead but don't plan on a profit.

  3. #3
    I assume you have a low temp system, using a cap tube for your metering device.
    I take it the compressor died. I hear you say the system was R-12.

    Why not replace the compressor with a like model, then charge it back up with MP-66?

    That way you wont have to deal with POE and secondly you wont have to fiddle with the cap tube.

    POE and cap tubes do not get along at all.
    First time the condensor gets dirty and overheats the system, the oil burns inside the cap tube and restricts it seriously!
    This is very bad indeed!

    With MP-66 you can run oil more agreeable with your capilary tubing.



  4. #4
    THANX FOR THE INFO SO FAR ,THE MP66 SOUNDS LIKE A GOOD IDEA
    I'AM JUST CONCERNED THAT THE EXISITING CAP TUBE MAY BE CONTAMINATED OR SHELACED FROM THE BURNOUT THANX FOR THE INFO

  5. #5
    Join Date
    May 2004
    Posts
    11,963
    R-12...

    Finding a compatible compressor or one sold for R12 can be tough. Purchase 134a compressor, change oil and use MP-66?

    He should change the cap tube anyway. He can get real close to the new size using Supco scale using BTU or HP or call Manufac and get cap size from them. Last option would be; get cap tube close and charge to superheat.

    If he needs to change condenser like Rocket said, he can change cap tube to TXV about as cheap. If he has the room for a unit with receiver.

    What are your thoughts?

  6. #6
    Join Date
    Jun 2001
    Location
    San Diego, CA
    Posts
    1,149
    when doing a compressor changeout, it is always wise to look at the cap tube. In fact, open it up and just before the cap tube put in a new filter drier. while it's open you can see if it's blocked or not. I've seen the spun
    filters plugged solid as a chunk of coal.

    With MP66, depending on the application - your cap tube may have to be longer - may not. Depends on your system
    and what range of ambient your condensor is likely to see.
    If the condensor is indoors - no problem.

    g

  7. #7
    Join Date
    Nov 2003
    Location
    Olympia, WA
    Posts
    47
    gdfromsd... do you work in alot of 70F kitchen or mechanical rooms?

    I've gotten into the habbit of replaceing the captube on any POE Compressor change out. It just not worth the extra R/R and Vacuum.
    Or taking apart the TXV before putting the new one in. Dead give away is seeing that what used to be green, which is now black dot.

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