Sluggish Temp Control

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?

Interesting observations.

I'd speculate that the scale on the dial is off on the controller. Maybe lower the temp of the controller to 20*? You might want to try moving the juice bottle so it's in contact with of very close to the two kegs in an effort to have the kegs influence the water temp more.

I have a chest freezer ith an analog Johnson controller and the bulb just hangs loose in the freezer. Seems to work OK.