Johnson Controls A421ABC-06 Temperature Control

The Johnson Controls A421ABC-06 is a professional-grade electronic temperature control engineered for high-performance HVACR applications. As the direct replacement for A419ABC-4, this unit offers a seamless transition for technicians upgrading legacy systems. Operating on 120/240 Vac, it provides a versatile single-stage control solution with an SPDT output relay, making it ideal for managing compressors, solenoid valves, or heating elements. This model features a wide temperature control range of -40?F to 212?F and includes an A99BB-600C temperature sensor with a 19.5-foot cable and a 2-inch probe for remote monitoring. The NEMA 1 enclosure is designed for surface mount or DIN rail installation, ensuring a rugged fit in mechanical rooms. Technicians will appreciate the front panel LCD and three-button touchpad, which simplify the adjustable anti-short cycle delay and sensor offset configurations to prevent equipment short-cycling and ensure precise thermal management across refrigeration and heating cycles.

Key Benefits for Technicians:

• Direct Replacement: Specifically designed to replace the A419ABC-4 with minimal field adjustment required.
• Precision Control: Features an A99 temperature sensor for accurate sensing across a broad -40 to 212?F thermal spectrum.
• Equipment Protection: Integrated adjustable anti-short cycle delay prevents rapid compressor cycling and extends component life.
• Versatile Mounting: Durable NEMA 1 enclosure supports both DIN rail and surface mount configurations for flexible installation.
• User Interface: High-visibility front panel LCD allows for quick status checks and simplified parameter adjustments in the dark.

Common Questions:

Can I use the old sensor from my A419 unit with the new A421ABC-06?
While the A421 is the replacement for A419ABC-4, it is highly recommended to use the included 19.5' A99BB-600C temperature sensor to ensure maximum accuracy and full compatibility with the updated electronic circuitry.

How do I configure the A421 for cooling vs. heating applications?
The Johnson Controls A421ABC-06 features an intuitive programming menu where you set the "ON" and "OFF" temperatures. Defining an "ON" temperature higher than the "OFF" temperature configures the electronic temperature control for cooling; reversing this order sets it for heating.

Is the wiring identical between the A419 and the A421?
The terminal layouts on the A421ABC-06 have been updated from the A419 series. You must reference the terminal labels on the 120/240 Vac block during installation as they are not index-matched to the older models.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.