Anyone here ever mess with big refrigeration plants?

I'm buying a 15' Hackney cold plate freezer van. It was a Blue Bell Ice Cream delivery truck in a former life and has a 3hp Copelametic compressor and multiple Hackney cold plates.

The problem is that I cannot get it to cool below about 37F...I think it should be going down to about -15F or so. I seem to recall that these systems can be set up to freeze or cool and I'm wondering if this one is set to cool instead of freeze.

Anyone have any insight?

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