A421GEF-02C Johnson Controls Temperature Control

Overview

The Johnson Controls A421GEF-02C is an electronic single-stage temperature control designed to provide reliable temperature management in demanding heating and cooling applications. Operating on 24 VAC, this unit features a rugged, watertight, and corrosion-resistant NEMA 4X (IP66) enclosure ideal for surface-mount installations in harsh, wet, or dusty environments. It comes equipped with a bright, adjustable backlit LCD screen and a simple three-button touchpad interface for convenient programming and monitoring.

Features

• Bright, adjustable backlit LCD screen with custom status icons for clear visibility.
• Three-button touchpad user interface with a restricted adjustment mode to prevent unauthorized tampering.
• Adjustable On and Off temperature setpoints for heating or cooling control, removing the need for internal jumpers.
• Adjustable anti-short cycle delay to protect compressors and inductive loads from short cycling.
• Temperature setback and sensor offset capabilities to shift setpoints via an external binary input switch.
• LED indicator providing clear visual confirmation of the output relay’s On/Off status.
• Single-pole, double-throw (SPDT) dry-contact output relay for versatile equipment wiring.

Specifications

• Supply Voltage: 24 VAC (20 to 30 VAC), 50/60 Hz, Class 2 or Safety Extra-Low Voltage.
• Power Consumption: Maximum 1.8 VA (100 VA power rating).
• Control Temperature Range: -40°F to 212°F (-40°C to 100°C).
• Temperature Accuracy: Less than +/- 1.8°F (+/- 1.0°C).
• Enclosure Rating: NEMA 4X, IP66 watertight surface mount.
• Included Sensor: A99BB-200C Positive Temperature Coefficient (PTC) sensor with a 6.6-foot (2.0 m) PVC cable.
• Output Relay: SPDT dry contacts.

Applications

• Commercial and industrial HVAC systems requiring precise single-stage temperature monitoring and regulation.
• Commercial refrigeration equipment such as walk-in coolers, reach-in boxes, and product display cases.
• Industrial process cooling and heating systems operating in washdown or weather-exposed environments.
• Environmental and ventilation control setups utilizing occupied/unoccupied setback scheduling via external timers.