A421ABG-02C Johnson Controls Control

Overview

The Johnson Controls A421ABG-02C is a single-stage electronic temperature control engineered for precise temperature management in commercial HVAC and refrigeration applications. It features a line-voltage 120 VAC operation and comes pre-wired with dual power cords (a 6 ft power cord with a grounded male plug and a cord with a grounded female outlet) for simple plug-and-play installation. Housed in a durable Type 1/IP20 high-impact thermoplastic enclosure suitable for surface or DIN rail mounting, this controller includes a bright, adjustable backlit LCD display and an A99BB-200C temperature sensor with a 6.6 ft cable.

Features

• Bright backlit LCD screen with adjustable brightness that clearly displays temperature, configuration parameters, and relay status.
• Simple three-button touchpad interface for rapid configuration setup and menu navigation.
• Single-pole, double-throw (SPDT) output relay to support both heating and cooling control strategies.
• Restricted user adjustment mode to limit unauthorized parameter changes.
• Adjustable anti-short cycle delay to protect compressors and inductive loads from rapid cycling.
• Temperature setback and sensor offset capabilities to enable efficient scheduling and sensor calibration.
• Integrated LED indicator providing clear visual cues for output relay On/Off status.

Specifications

• Supply Voltage: 120 VAC, 50/60 Hz
• Temperature Control Range: -40 to 212°F (-40 to 100°C)
• Output Relay Rating: SPDT, 12 Amp continuous load capacity
• Enclosure Rating: Type 1 (NEMA), IP20 high-impact plastic for indoor surface or DIN rail mounting
• Temperature Accuracy: Less than +/- 1.8°F (+/- 1.0°C)
• Included Sensor: A99BB-200C Positive Temperature Coefficient (PTC) temperature sensor with a 6.6 ft (2.0 m) cable
• Power Consumption: Maximum 1.8 VA

Applications

• Temperature monitoring and control for single-stage commercial refrigeration systems.
• Temperature regulation for commercial HVAC equipment, heating elements, and ventilation systems.
• Precise environmental management for food service equipment, walk-in coolers, and beverage cooling systems.
• Homebrewing, fermentation temperature control, keezer setups, and wine preservation spaces requiring stable temperature environments.