A421ABC-02C Johnson Controls Temperature Control

Overview

The Johnson Controls A421ABC-02C is a line-voltage, single-stage electronic temperature control equipped with a single-pole, double-throw (SPDT) output relay. It features a bright backlit LCD screen and a three-button touchpad interface designed to efficiently manage heating or cooling equipment across various refrigeration and HVAC applications.

Features

• Easy-to-read, adjustable backlit LCD screen with custom status icons
• Simple three-button touchpad interface for quick setup and adjustments
• Adjustable On and Off temperature setpoints eliminating the need for internal jumpers
• Adjustable anti-short cycle delay to protect compressors from short cycling
• Temperature setback control via a dry-contact binary input circuit
• High and low temperature setpoint stops to restrict user adjustments

Specifications

• Supply Voltage: 120/240 VAC, 50/60 Hz
• Temperature Control Range: -40 to 212°F (-40 to 100°C)
• Differential Adjustment Range: 1 to 30°F
• Output Relay: SPDT dry-contact switch
• Enclosure Rating: Type 1 (NEMA), IP20 plastic suitable for surface or DIN rail mounting
• Included Sensor: A99BB-200C positive temperature coefficient (PTC) temperature sensor with 6.6 ft cable

Applications

• Control of single-stage refrigeration or HVAC equipment
• Direct switching of boilers, chillers, or circulation pumps
• Cooling-tower fan cycling and fan or damper operation
• General heating or cooling control in greenhouses, walk-in boxes, or equipment cabinets