A421AEC-01C Johnson Controls Temperature Control

Overview

The Johnson Controls A421AEC-01C is a line-voltage, single-stage electronic temperature control designed to manage a wide variety of single-stage refrigeration or HVAC equipment. It features a watertight, corrosion-resistant NEMA 4X (IP66) surface-mount enclosure and includes an A99BB-25C PTC temperature sensor with 9-7/8 inch leads.

Features

• Bright, adjustable backlit LCD screen displaying temperature, parameters, and system status
• Simple three-button touchpad interface for programming and basic adjustment
• Adjustable On and Off temperature setpoints for heating or cooling control
• Single-pole, double-throw (SPDT) output relay with an LED indicator showing the relay status
• High and low temperature setpoint adjustment stops to restrict user adjustment ranges
• Adjustable anti-short cycle delay to protect compressors from short cycling
• Switch-activated temperature setback and adjustable sensor offset capability

Specifications

• Supply Voltage: 120/240 VAC, 50/60 Hz
• Temperature Control Range: -40 to 212°F (-40 to 100°C)
• Temperature Accuracy: Less than +/- 1.8°F (+/- 1.0°C)
• Enclosure Rating: NEMA 4X / IP66 watertight thermoplastic
• Switch Action: SPDT output relay
• Sensor Included: A99BB-25C PTC temperature sensor with 2-inch standard probe and 9-7/8 inch PVC cable

Applications

• Free-cooling and duty-cycle ventilation systems
• Single-stage HVAC and heating equipment control
• Commercial refrigeration management, including reach-in boxes, display cases, and walk-in coolers
• Medium-temperature cooling applications needing adjustable anti-short cycle delays or passive defrost options