The A421 series controller is a single stage, electronic temperature controller with a single-pole, double-throw (SPDT) output relay. The controls feature an adjustable backlit LCD for viewing the temperature and status of other functions and a three-button touchpad for setup and adjustment. A LED indicates the on / off status of the output relay. The A421 controller provides both heating or cooling control, sensor offset, temperature setback, adjustable anti-short cycle delay and a restricted user adjustment mode. The temperature units can be displayed in f or c. The temperature adjustment range is -40 to 212 Fahrenheit or -40 to 100 Celsius.
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