Johnson Controls A19BAB-3 Temperature Control

The Johnson Controls A19BAB-3 is a rugged mechanical temperature control designed for high-accuracy space temperature monitoring in demanding HVACR environments. Engineered with a Single-Pole Single-Throw (SPST) switch configuration, this unit operates on an open high action, making it an essential component for heating applications where the circuit must break upon reaching the setpoint. With a versatile voltage range of 24 to 277Vac, it integrates seamlessly into various control strings without requiring additional transformers. This model features a 35 to 95 degree F setpoint range and a 3 degree F fixed differential, ensuring precise thermal management and preventing frequent equipment short-cycling. The coiled bulb and capillary design, measuring 1 3/8" x 2 1/4", provides superior sensitivity for ambient air sensing. Built for the field, the automatic reset functionality and knob range adjuster allow for immediate adjustments and reliable operation without manual intervention after a high-limit event.

• Universal Voltage Compatibility: Supports 24Vac to 277Vac, providing flexibility for low-voltage controls or line-voltage heating systems.
• Precise Setpoint Control: Features a fixed 3 degree F differential to maintain consistent environments and reduce mechanical wear.
• High-Sensitivity Sensing: The coiled bulb space temperature control maximizes surface area for rapid response to ambient air changes.
• Contractor-Friendly Design: Equipped with a knob range adjuster for fast, tool-free setpoint calibration during service calls.
• Reliable Switching: SPST Open High logic ensures fail-safe operation in standard heating and ventilating applications.

Is the Johnson Controls A19BAB-3 suitable for cooling applications?
No, this specific model is an Open High control, which opens the circuit on temperature rise. It is primarily used for heating or as a high-limit cutout. For cooling or fan-on-rise applications, an Open Low (normally open) or SPDT model is required.

Can I use this control for liquid immersion?
While the coiled bulb is optimized for air temperature sensing, it can be used in some immersion applications if paired with a compatible bulb well. However, the coiled design is specifically intended for maximum airflow contact in space sensing.

Does the A19BAB-3 require a manual reset after a trip?
This unit features automatic reset logic. Once the sensed temperature drops below the setpoint minus the 3 degree differential, the contacts will automatically re-close to resume normal operation.

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.