Johnson Controls A19AAF-12 Temperature Control

The Johnson Controls A19AAF-12 is a robust mechanical temperature control engineered for high-performance heating and general-purpose HVACR applications. Built with a single-pole double-throw (SPDT) switch configuration, this remote bulb controller delivers precise temperature regulation across a broad 25 to 225?F setpoint range. The unit features an automatic reset mechanism and a 3.5?F fixed differential, ensuring consistent cycling and system stability without the risk of cross-ambient interference. Designed for 24V to 277VAC electrical systems, it includes a 10' capillary and a 3/8" x 3" sensing bulb for flexible mounting in tanks or air ducts. This industrial thermostat is the specified direct replacement for the A19AAF-12C and A19AAC-49 models, offering contractors a reliable solution for field service and equipment upgrades. Technical adjustments are streamlined via the integrated screwdriver slot range adjuster, allowing for secure calibration in the field.

• Universal Compatibility: Operates on any voltage from 24VAC to 277VAC, making it a versatile HVAC replacement part for diverse mechanical systems.
• Precision Sensing: Features a liquid-filled 10-foot capillary and remote sensing bulb for accurate temperature monitoring, even when the control head is mounted away from the heat source.
• Rugged Reliability: The NEMA 1 enclosure and heavy-duty SPDT contacts are designed to withstand demanding industrial environments and provide long-term switching performance.
• Standardized Fit: Directly replaces legacy models A19AAF-12C and A19AAC-49, reducing downtime during emergency repairs and maintenance.

Common Questions

Can the A19AAF-12 be used for both heating and cooling?
Yes, the SPDT switch action allows for wiring in either a "close on rise" or "open on rise" configuration, making it suitable for heating or cooling/refrigeration applications within its 25-225 degree F range.

Is this model compatible with immersion wells?
The 3/8" x 3" sensing bulb is compatible with standard Johnson Controls bulb wells (like the WEL14A series) for closed tank or pressurized liquid applications.

Does this unit require a manual reset?
No, this model is an automatic reset temperature control, meaning the contacts will return to their normal state once the temperature moves past the fixed differential threshold.

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.