Johnson Controls Analog Temperature Controller (A19)

The Analog Temp Controller comes prewired, so you just plug and play! It operates by overriding the internal thermostat in a refrigerator or freezer and gives the brewer greater control over the fermentation. Precise control of fermentation temperature is one of the most beneficial things you can do to improve your home brew beer.

It is also ideal for controlling the serving temperature of your kegerator or keezer.

When hooked up to a refrigerator, it turns the compressor on when the ambient temperature rises above your programmed temperature; when hooked up to a heater, it activates when the temperature drops too low. A sensor probe monitors the temperature inside.