I converted a Grunert 120V refrigeration system to a 12 V system using
a Glacier Bay motor direct coupled to a Bitzer IIY compressor using
R134A. I´m using a 1 ton expansion valve in the refrig.

The system works very well, but I´m having a problem with the
refrigerator holding plate. The bottom of the holding plate is at -10F
and the top of it is +18. It freezes at +18. This temperature
differential is causing the system to cycle too often.

What is causing this problem? The freezer runs fine. The system starts
out at about 10 PSI and in 10 to 15 minutes works itself down to -10
to -12 Hg.

Thanks, Geoff