Johnson Controls A421GEF-01C Temperature Control

The Johnson Controls A421GEF-01C is a professional-grade electronic temperature control designed for precise thermal management in demanding HVACR environments. Operating on 24 VAC, this unit offers a broad setpoint range of -40 to 212?F, making it suitable for both refrigeration and heating applications. As the direct replacement for A419GEF-1, it features an upgraded front panel LCD for real-time monitoring and simplified on/off temperature control adjustments. The enclosure is NEMA 4X rated, ensuring durability against moisture and corrosion when used in wash-down or exterior environments. For installation versatility, the A421GEF-01C supports both DIN rail mount and surface mounting, and comes standard with a high-accuracy A99 temperature sensor on a 9-7/8 inch lead. This single-stage control provides reliable HVAC relay switching with field-configurable parameters for offset, differential, and cycle delay.

Key Benefits

• Enhanced Enclosure Integrity: The NEMA 4X/IP66 housing provides superior protection for wash-down environments or high-humidity mechanical rooms.
• Seamless Integration: Engineered specifically as a drop-in replacement for A419GEF-1, minimizing downtime during field upgrades.
• Advanced Diagnostics: The backlit LCD provides immediate visual feedback on sensor status and relay positioning to streamline troubleshooting.
• Mounting Versatility: Dual-support for surface and DIN rail mounting allows for clean cable management within standard control panels.
• Adjustable Differential: Field-adjustable settings allow for precise control over equipment cycling to optimize compressor longevity and system efficiency.

Common Questions

Does this unit require a separate transformer for 24V operation?
Yes, the Johnson Controls A421GEF-01C requires a dedicated 24 VAC power source. Ensure your control circuit matches this voltage to prevent board damage.

Can I extend the lead length of the included A99 sensor?
Yes, the sensor lead can be extended up to 300 feet using shielded 22 AWG cable, provided you account for resistance changes in your calibration settings.

Is this control suitable for both cooling and heating applications?
Specified for versatility, the A421 series can be configured for either heating or cooling modes via the jumper settings on the circuit board or the digital menu.

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.