VT25 upper unit freeze up

[Randy G]

Please let me thank Jim for kindly getting me set up to access this terrific knowledge base.  I have owned a Vendo H 63 A with a VT25 refrigeration unit for quite awhile.  I have done a partial restoration over time myself (paint, body filler, gaskets, decals).  The VT25 unit is original - but with an successful update several years ago by Alan Huffman.  The unit still cools (thermo setting 1-2), but the upper unit frosts up over approximately 10 days.  The compressor appears to run continuously.  The upper unit fan runs continuously as well - no problem.

I have to unplug the machine to defrost.  I have replaced the main door gasket and vending door gasket within the year.  I assume that ambient air intake is minimal to the bottle area.

I am obviously not refrigeration knowledgeable.  Any help you can provide me in troubleshooting is MOST welcome. No issues with previous work, just have a very old unit and need a solution.

I would like to gain some understanding of cooling issues and find a local solution to avoid shipping the unit.

Thank you very much for your time and kindness.
Randy Gray

[MoonDawg]

       Welcome Randy.
       Sorry to see that your successful update has turned unsuccessful. 
       Your system is now low on freon, possibly due to a very slow leak at a recent solder joint.
       Remove the unit again and take it to any refrigeration service center.

[Randy G]

Thanks very much for your time, Moondawg.  I guess successful sometimes really means "successful for awhile".

I understand that the refrigerant used is "hot shot".  If I am having it repaired, evacuated and recharged, is that what I want to use, or do you suggest another refrigerant?

Thanks again for helping me out.
Randy

[MoonDawg]

         The unit originally used R-12, it's really cold stuff.