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/Off status of the output relay. The A421 Controls are available in 120 VAC and 240 VAC models.
The A421 Control with Defrost allows you to set up regular, passive defrost periods of 1 minute to 99 minutes. The defrost interval can range from 2 hours to 24 hours, or be set to 0 for no defrost interval. You can also start or stop a defrost off-cycle in two ways: press the three-button touchpad on the Advanced Menu or connect a momentary switch to the Binary Input (BIN).
The A421 also provides 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°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.
Refer to the A421 Series Electronic Temperature Controls Product Bulletin (LIT-12012219) for important product application information.