Product Overview

A421 Series Standard Electronic Temperature Controls with and without Power Cords Product Bulletin
2
Applications
The A421 Electronic Temperature Control can be used
to control a wide variety of single-stage refrigeration or
HVAC equipment. See Table 2 for application
information by control type.
Sample temperature control applications include:
• temperature monitoring and alarming
• on/off control of boilers and chillers
• boiler and chiller pump control
• heating or cooling control
• cooling tower fan control based on water
temperature
• supply, makeup, and mixed air temperature control
• temperature actuated valve control
• supply and makeup air damper and fan control
• condenser fan control based on condenser
temperature.
Adjustable Sensor Offset Allows you to adjust the displayed temperature to the actual sensed
temperature.
Optional Restricted Adjustment Mode Allows you to restrict the On/Off adjustment to your defined temperature
range.
Sensor Failure Mode Allows you to select the relay On/Off state in the event of a sensor or
sensor wire failure.
Backlight Brightness Level Allows you to adjust the LCD backlight intensity.
Table 1: Features and Benefits (Part 2 of 2)
Features Benefits
Figure 2: Standard Temperature Control with
Type 4X/IP66 Enclosure
Figure 3: Corded Temperature Controls with
Type 1/IP20 and Type 4X/IP66 Enclosures
IMPORTANT: Use this A421 Series Electronic
Temperature Control only as an operating control.
Where failure or malfunction of the A421 Series
Control could lead to personal injury or property
damage to the controlled equipment or other
property, additional precautions must be designed
into the control system. Incorporate and maintain
other devices, such as supervisory or alarm systems
or safety or limit controls, intended to warn of or
protect against failure or malfunction of the
A421 Series Control.