Review on 🔍 Improved SEO: Johnson Controls A421ABC-02C A421 Series Electronic Temperature Control, -40°F to 212°F Range, SPDT by Brett Jarvis

Bought to control a submerged heating cable in a workshop floor drain. The pipe was frozen below 20F. The device is really versatile. It is fitted with an external remote temperature sensor to control the on/off set points which are fully programmable. Can be used for heating or cooling (but NOT both - it only has one relay). The temperature sensor cannot be submerged in water, but is moderately splash-proof when installed correctly. The display shows the current sensor temperature. Units of measurement (Celsius or Fahrenheit), high/low activation temperature, anti-cycling, delta options, etc. are all fairly easy to program. Line outlet only from below, not on the side or above. Terminal screws for connections, and space is limited. A single wire nut is unlikely to fit, even if you have to. I would definitely buy another one for my next project.