The A421 Series Standard Electronic Temperature Controls are single stage, electronic temperature controls 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. An LED indicates the On or Off status of the output relay.
The A421 Controls are available in low-voltage 24 VAC and high-voltage 120 VAC or 240 VAC models, which provide options for most refrigeration and HVAC applications.
The A421 Controls provide heating or cooling control, sensor offset, temperature setback, adjustable anti-short cycle delay, and a restricted user adjustment mode. The control can display the temperature units in °F or °C. The temperature adjustment range is -40°F to 212°F or -40°C to 100°C.
The A421 Controls are available in Type 1/IP20 high-impact plastic enclosures suitable for surface or DIN rail mounting and Type 4X/IP66 watertight, corrosion-resistant surface mount enclosures, as shown in the following figure.
Some A421 Series Control models are equipped with factory-installed power cords. The power cords provide convenient plug-in connection and control of 120 VAC heating and cooling equipment.