I just acquired a chest freezer, and bought an analog Johnson Control unit for it last weekend. Before I plugged in the controller, I tested out the freezer. Just plugging it in and letting it run for eight hours, I put a themometer inside for about ten minutes, and registered the air temp somewhere near 5 degrees.
I plugged in the controller, and put a large juice bottle of water inside, and stuck my probe inside it. I let it run three days, and the temperature of the water never dropped below 40, even though I have the controller set for 30. I put another thermometer onto the carrier ring of the juice bottle, and measured the air temperature at about 20.
So, I figured, close enough, and went to crash cool my batch of beer for several days. When I pulled out my bucket, the brewmometer registered the bucket at near 50 degrees, and the thermometer inside the juice bottle was around 45 degrees.
So... anyone have any ideas why I can't get my fluids closer to 32 degrees?