Originally Posted by JJL
You're going to want it set to cooling and to cut out. You'll want the set point at 40 and a dif of 4 or 5 to keep it between 40 & 45.
In this setup, the freezer will turn ON at 45, and turn off at 40. The freezer will turn on at the SP + Differential, which is 45. It will turn OFF at the SP (Cut-out).
The Cut-in and Cut-out is what they controller will do when the SP is reached.
Keep in mind that even though the freezer has turned out, there is a chance that the temp could drop a degree or two as the cold soaks into the freezer.
And a small fluctuation in air temp is not a concern. It's the temp inside the fermenter that matters, and it will be more stable, as it has such thermal mass to not lose or gain temp as quickly.
I really suggest you re-read the manual a few times. There is a small section that should give a visual example of how the cut-in and control mode work together. It's not hard to understand if you can "see" it.