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Thread: R12 pressures?

  1. #1
    Join Date
    Jul 2005
    Hi, I've got an old coke machine that isn't cooling well. Cleaned lint and dust off coils, etc. and still only getting down to about 46*f in the box. I've never worked with r12 before. What sort of pressures should I expect?
    My only experience is with r22 in water-source heatpumps. I just don't know what to expect for start-up and running pressures.

    It's a cool old machine, the kind you could pop the top off a bottle at the gas station or fire station and fill a cup up without paying while the bottle is still in the machine if you were an idiot kid like I was I'll use it for my home brew savings account, you know... charge myself to drink my own beer so I don't have to get into the rainy-day money for the next batch of hops and grain.

    Also, I haven't put my guages on it yet, will a nitrogen purge clean them up okay to go back to r-22?

    Appreciate the help here.

  2. #2
    Join Date
    Oct 2004
    OZ Aka SW Florida
    Does it have service access?

    Check the RLA to the name plate?

    They would hold 1 to 2 lbs of gas, the old ones.

    Are you sure it is low on gas, and not cycleing off on t-stat?
    Refrigeration...Finding the Wright Wrench to pound in the correct..Screw

  3. #3
    Join Date
    Sep 2001
    East Stroudsburg, PA
    What does your PT chart tell you?

    It's still on every single PT chart that I've ever seen......

  4. #4
    Join Date
    Jul 2005
    CondenseDave: Silly me. I can look at my guages without ever putting them on for the PT, doh! Thanks.

    Cracker; yip I can get to it. Haven't put a mmeter on it yet. t-stat sensor could be dislodged or defective? The bottle I tested in it wasn't cold. Fluke says 46* in the box and T-stat is set at 36*f

    I think the people that had it before left it on the porch all winter.

    On one hand, it is a cool machine and I want it to live. On the other, I've never dealt with a 'fridge' before.


    I really appreciate your guys's help here. I want to be a better tech. Thank you for teaching me.

  5. #5
    Join Date
    Apr 2005
    Australia : Queensland
    Check all the seals , that there is no heat entering from unwanted places . check coils , put a set of gauges on.
    The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman.

  6. #6
    Somebody mention my name ... ?

    today the pressures are kinda down. everything is smoothing out and fine.
    Now YESTERDAY... that was another story. The head pressure was terribly high due to "hi tension iussues"... (those of you who are married... y'all know what I mean)

    R-12... now THAT was a real refrigerant!!!

    [Edited by R12rules on 11-10-2006 at 04:00 PM]

  7. #7

    if it's one of mine you have service access

    Hello Gentlemen,
    This is my first post, and I'm sure it won't be my last.
    Started my own little business now that my "honeydew" list is complete.

    Lojo, I retired from Coke in 1998. We retired that machine long before. If it was one of my (our) machines you have service access (Northeast region). Sometimes the powers that be are cheap and don't want to spend the extra but......
    Somehow,in the the cobwebs of the cranial cavity I'm thinking 150/28 on start-up, watch RLA, 125/18 near temp, cap tube...units have been rebuilt and altered so many times we don't go by plate but by frost back.

    With that said, I refer you to all the replies, simply saying like the sign on the shop wall "Get back to BASICS".

    Good Luck....crack open a cold one on me...

  8. #8
    Join Date
    Apr 2001
    Camel City, NC


    welcome to the site. I won't start with the coca-cola or coke jokes.
    Be safe not fast. body parts don't grow back

  9. #9


    lojo, This is the mojo, hey that sounds cool. Wake up because econoline has something to say.And econoline welcome to HVAC and R! talk. Ah yes, the good old days of dichlorodifluoromethane

  10. #10
    Join Date
    May 2000
    Monmouth Junction-NJ-USA
    Econ that is exactly what I was thinking. Down to temp and18 lb suction and walk away from it. Do a lot of schools with the portable milk boxes and that is where they all come in. Red paint under the blue. Was made by vendolator for Coke/Pepsi. I put a new comp in this Pepsi machine 7oz bottles. 134-A and a new cond fan motor and changed some dry rotted wiring. This is late 50 early 60 vintage.

    If you really know how it works, you have an execellent chance of fixin' er up!

    Tomorrow is promised to no one...

  11. #11
    Thanks for the welcome guys, rayr, cool pics...I'm havin' flashbacks

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