LCD - PENN Controls - A421ABG - A421ABJ - A421AEJ - Electronic Temperature Control - A421 Standard Model

A421 Series Standard Electronic Temperature Controls with Power Cords Installation Guide

PENN Controls
Product name
A421 Standard Model
Document type
Installation Guide
Part number
Document revision
Revision date

The A421 Series Control has a backlit LCD screen (Figure 1). You can adjust the LCD brightness. During normal operation, the LCD displays the Main screen, which provides the following information:

  • Temperature sensed at the A99 sensor
  • Selected temperature units (°F or °C)
  • Mode of operation (Flame = Heating mode, Snowflake = Cooling mode)
  • Binary Input status (BIN) when a user-supplied binary input (switch) is connected and closed to use the temperature setback feature.

During setup and adjustment, the LCD displays the parameter code screens and the parameter value screens. See the A421 Control parameter setup menus for more information.