Penn A421 Series - Off-Cycle Defrost Control

Dimensions
Figure 1: A421 Control with Type 1 (NEMA), IP20 enclosure dimensions, in. (mm)
Figure 2: A421 Control with Type 4X (NEMA), IP66 enclosure dimensions, in. (mm)
Off-Cycle Defrost control
You can use the A421 Control with Off-Cycle Defrost to set up regular, passive defrost periods of 1
minutes to 99 minutes. The defrost interval can range from 2 hours to 24 hours, or you can set it to
0 for no defrost interval. You can also start or stop a defrost cycle in the following two ways: use the
three-button touchpad on the Advanced Menu or connect a momentary switch to the binary input
(BI).
A421 Series Electronic Temperature Controls with Off-Cycle Defrost Installation Guide2