A421GEF-01C Johnson Controls Temperature Control

Overview

The Johnson Controls A421GEF-01C is a single-stage electronic temperature control designed to provide reliable heating or cooling control in a variety of HVAC and refrigeration applications. It comes equipped with a single-pole, double-throw (SPDT) output relay and features a bright, adjustable backlit LCD screen along with a simple three-button touchpad user interface. The unit is housed in a watertight, corrosion-resistant NEMA 4X (IP66) enclosure suitable for surface mounting and operates on low-voltage 24 VAC power. It includes a high-performance A99BB-25C PTC temperature sensor with a 2-inch standard probe and a 9-7/8 inch cable.

Features

• Easy-to-read, bright backlit LCD screen with adjustable brightness.
• Simple three-button touchpad interface for navigating basic and advanced programming menus.
• Single-pole, double-throw (SPDT) dry-contact output relay.
• Adjustable On and Off temperature setpoints for heating or cooling configurations.
• High and low temperature setpoint adjustment stops to restrict user alterations.
• Adjustable anti-short cycle delay to protect compressors from short cycling.
• Temperature setback capability via switch-activated binary input.
• Temperature sensor offset adjustment to account for long wire lead resistance.
• Configurable sensor failure mode (relay energized or de-energized).
• NEMA 4X (IP66) watertight, high-impact thermoplastic enclosure that can be rotated 180 degrees.

Specifications

• Supply Voltage: 24 VAC (20 to 30 VAC), 50/60 Hz, Class 2 or Safety Extra-Low Voltage (SELV).
• Power Consumption: Maximum 1.8 VA.
• Temperature Control Range: -40 to 212°F (-40 to 100°C).
• Temperature Accuracy: Less than +/- 1.8°F (+/- 1.0°C).
• Relay Output: SPDT dry contacts; 15.0A resistive @ 24 VAC.
• Sensor Type: A99BB-25C Positive Temperature Coefficient (PTC) sensor with a 9-7/8 inch PVC cable.
• Enclosure Rating: NEMA 4X / IP66 watertight and corrosion-resistant.
• Operating Ambient Temperature: -40 to 140°F (-40 to 60°C).
• Operating Humidity: 0 to 95% RH non-condensing.

Applications

The A421GEF-01C is ideal for commercial and industrial single-stage HVAC and refrigeration equipment. It is frequently applied in walk-in coolers, reach-in boxes, display cases, food storage units, and commercial beverage coolers. Due to its NEMA 4X watertight enclosure, it is highly suited for wash-down environments, outdoor environments, and locations exposed to high moisture, dust, or corrosive elements.