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  1. #1
    Join Date
    Nov 2006
    Location
    Oregon
    Posts
    853

    Monitor top conversion from sulfur dioxide to R-12

    My fridge developed a sulfur dioxide leak in the evaporator. Here's my completed conversion to R-12. I cheated and performed a heart transplant.
    Attached Images Attached Images     

  2. #2
    Join Date
    Nov 2006
    Location
    Oregon
    Posts
    853
    This was the donor.

    P.S. Antique refrigeration is a PIA!!
    Attached Images Attached Images  

  3. #3
    Join Date
    Feb 2006
    Location
    Phoenix,AZ
    Posts
    2,891
    Do you mind explaining how it worked originally? I never heard of sulfur dioxide, nor do i know what that thing is on top of the fridge.

  4. #4
    Join Date
    Sep 2002
    Posts
    12,571

    Why didn't you keep the evap and float?

    and go to 134 instead of 12?

    PHM
    --------
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  5. #5
    Join Date
    Nov 2006
    Location
    Oregon
    Posts
    853
    Quote Originally Posted by Poodle Head Mikey View Post
    and go to 134 instead of 12?

    PHM
    --------
    The evaporator is rusted out (see image). Besides that the mineral oil used in SO2 refrigeration units is likely not compatible with PAG used in R134A systems.

    I'm pretty sure my compressor is OK unless the moisture sucked in, (ie SO2 evaporators operates at less then atomospheric pressure), caused an adverse sulfuric acid reaction inside the hermetic unit.

    The stubs from the condensor are crimped shut should I ever find a replacement evaporator. For now R-12 works just fine - at least the beer is cold!!

  6. #6
    Join Date
    Nov 2006
    Location
    Oregon
    Posts
    853
    Quote Originally Posted by kbghdg View Post
    Do you mind explaining how it worked originally? I never heard of sulfur dioxide, nor do i know what that thing is on top of the fridge.
    The top part is the hermetic compressor unit with the condensor coils circling around it. The evaporator is a similar to modern evaporators except it's cast iron and prone to rust.

    They used a float to control the liquid refrigerant entering into the evaporator. (kind of like a toilet valve)

    SO2 is miserable refrigerant to work with. A few strong huffs and you might be dead. These monitor tops are pretty robust but imagine a major refrigerant leak back in the 20's when people lived in very small houses. If the obnoxious smell didn't wake you up in time you'd likely be dead. SO2 refrigeration units were like a chemical weapons inside of homes. Freon R-12 was a godsend given the primitive refrigerants at the time.

    The later model monitor tops had stainless steel evaporators and were much safer however I would not put them in living quarters - the garage is close enough.

  7. #7
    Join Date
    Sep 2002
    Posts
    12,571

    What were the ones with the bronze evaps?

    They looked like that one you pictured but were all bronze. What refrigerant did they use?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  8. #8
    Join Date
    Nov 2006
    Location
    Oregon
    Posts
    853
    Quote Originally Posted by Poodle Head Mikey View Post
    They looked like that one you pictured but were all bronze. What refrigerant did they use?
    I have no ideal. Maybe methyl formate or anhydrous ammonia. However I don't think GE did ammonia.

  9. #9
    Join Date
    Sep 2002
    Posts
    12,571

    Ammonia tears up brass

    So maybe methylene chloride? I was just curious. All the one's I've ever seen were dead empty and after I fixed the leaks I charged them with R-12. When it was a dollar per pound. <g>

    PHM
    -------


    Quote Originally Posted by davefr View Post
    I have no ideal. Maybe methyl formate or anhydrous ammonia. However I don't think GE did ammonia.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  10. #10
    Join Date
    Sep 2011
    Location
    waterford ny
    Posts
    4
    I have a monitor top that the gas is all leaked out. I like your conversion and would like to do the same thing? I can get a small refrigertor like the one you used on craigs list that works for $25.00 is there any thing i need to know before I buy it? The coils are mounted on the back like the one you show. Will I have to disconect the lines to install every thing and then recharge the system or can i get away with out doing that? where did you install the on and off switch? <Email addresses are not permitted in post, please put it in your profile, thank you>
    Last edited by beenthere; 01-03-2013 at 07:15 PM. Reason: email

  11. #11
    Join Date
    Nov 2008
    Location
    Hudson Valley, NY
    Posts
    203
    the C-A modle had METHYL FORMATE in them bad stuff stay away !!!!!!!!!!!!

  12. #12
    Join Date
    Sep 2011
    Location
    waterford ny
    Posts
    4

    C-a ?

    Quote Originally Posted by A1 Burt View Post
    the C-A modle had METHYL FORMATE in them bad stuff stay away !!!!!!!!!!!!
    C-A Modle ? The amonia deoxide is all leaked out ? I am going to try the coversion taht you show?

  13. #13
    Join Date
    Oct 2009
    Location
    Raleigh, NC
    Posts
    799
    Why is Methyl Formate "bad stuff"? I mean, it is a toxic chemical, but it isn't dangerous when handled carefully. It is even a liquid at room temperature. I would think ordinary gasoline is much more dangerous.

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