Johnson A419 Pre-Wired Digital Temperature Controller. This is an overriding thermostat. You can plug in into a heating or a cooling device (change jumpers to switch between heating or cooling) to more precisely control temperature.

Common homebrewing applications include controlling a deep freezer or refrigerator for use as a kegerator or fermentation chamber. Generally, you would turn the device all the way up (most cooling power), place the A419’s probe inside, plug the appliance into the A419 and plug the A419 into the wall. Includes ASD (anti-short cycle delay) to help increase compressor life. Has a configurable set point and a configurable differential. It can also display in both deg C and deg F.

I have used two of these. One for my kegerator and one for my fermentation deep freeze. I started out with an analog model on my kegerator and like control (and temperature readings) of the A419 so much that I replaced the analog with an A419. These are great temp controllers!

Johnson Controls Digital Thermostat Control Unit

Also: Johnson Digital Temp Controller at MoreBeer | Inkbird Dual Stage Temp Controller

Related: A419ABG-3C User Manual | Tips and Gear for Your Kegerator

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