Setting the control to Restricted Adjustment mode - PENN Controls - A421ABD - A421AED - Electronic Temperature Control - A421 Off‐Cycle Defrost Model

A421 Series Electronic Temperature Controls with Off-Cycle Defrost Installation Guide

Product name
A421 Off‐Cycle Defrost Model
Document type
Installation Guide
Document revision
Revision date

About this task

In this task you set up the restricted adjustment feature.


  1. To make sure that the A421 is not in restricted mode, position the jumper on both pins. See Figure 1.
  2. Select the OFF and On values that define the application’s required control band (Figure 1).
  3. Change the HtS and LtS temperature values to define the restricted adjustment range (Figure 1).
  4. Disconnect power to the control and reposition the jumper to one pin (Figure 1). Reconnect the power.
    Figure 1. Repositioning the jumper to restrict control adjustment


Control adjustment is now restricted to changing only the OFF value, which shifts the On and OFF control band within the restricted adjustment range defined by HtS and LtS (Figure 1).

Note: To completely restrict and lockout all user adjustment on the control, set the HtS value equal to the On or OFF value and the LtS value equal to the OFF or On value. Then the (On to OFF) control band is equal to the restricted adjustment range, LtS to HtS, and the OFF value cannot be adjusted in the restricted mode.