Johnson Controls A350AA-1 Temperature Control

The Johnson Controls A350AA-1 is a core component of the System 350 modular electronic control platform, designed for precise on/off temperature control in commercial HVACR applications. This 24Vac electronic temperature control features a setpoint range of -30 to 130°F, making it a reliable choice for walk-in coolers, reach-in freezers, and space heating systems. The unit utilizes a SPDT relay output, providing the flexibility needed for various wiring configurations, while the included A99BC-25 silicon sensor ensures accurate thermal feedback with minimal drift over time. Field calibration is simplified via the adjustable differential (1 to 30°F) and offset (1 to 30°F) potentiometers, allowing for tight cycle management and improved equipment longevity.

Technical Specifications & Performance Benefits:

• Precision Thermal Sensing: Includes the A99BC-25 sensor for high-accuracy PTC thermistor performance.
• Modular Scalability: Seamlessly integrates with S350 stage modules for multi-stage sequencing.
• Broad Operating Range: Covers a wide setpoint span from -30 to 130 degrees F for versatile installation.
• Adjustable Hysteresis: Dial in a 1 to 30°F differential to prevent short-cycling of compressors or furnace fans.
• Durable Construction: NEMA 1 high-impact plastic enclosure suitable for surface or DIN rail mounting.

Common Contractor Questions:

What is the maximum distance for mounting the A99 sensor from the A350AA-1?
The A99 series sensors can be extended up to 250 feet using 22 AWG shielded cable, provided the run avoids high-voltage interference. For longer runs, recalibration of the offset may be necessary to account for lead wire resistance.

Can the A350AA-1 replace a standard mechanical thermostat?
Yes, this electronic control provides superior accuracy and a tighter differential compared to mechanical bellows-style controls, though it requires a 24Vac power source to operate the internal circuitry and relay.

How do I configure the module for heating vs. cooling?
The SPDT relay allows for both operations; use the Normally Open (N.O.) terminals for cooling loads (close on rise) and the Normally Closed (N.C.) terminals for heating applications (open on rise).

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.