LIT-1900935
2020-04-14
A421 Series Electronic
Temperature Controls with Off-
Cycle Defrost Catalog Page
A421ABD, A421AED, A421AED
Description
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.