Johnson Controls A19AAB-40 Utility Thermostat

The Johnson Controls A19AAB-40 Utility Thermostat is a heavy-duty remote bulb temperature control designed for high-range heating and industrial applications. Built for dependability in demanding environments like industrial ovens, crop drying, and commercial space heating, this mechanical thermostat features a liquid-filled sensing element that ensures precision repeat accuracy regardless of barometric pressure or cross-ambient conditions. It operates on 120/208/240 Vac with SPST contacts configured to open on rise, acting as a reliable high-limit safety or operating control within a 100?F to 240?F set point range.

The 12-inch non-armored capillary and 3/8" x 3-1/2" bulb offer responsive thermal sensing, while the NEMA 1 enclosure provides a rugged, dust-tight housing for the internal Pennswitch snap-acting mechanism. With a fixed differential of approximately 6?F (3.3?C), this unit maintains tight process control without excessive cycling. For contractors looking for a high-limit cutout or heat-only controller, the A19AAB-40 is a standard-tier solution for maintaining safety across high-temperature HVACR systems.

• High-Temperature Reliability: Supports a broad 100-240?F range for specialized heating and industrial process applications.
• Versatile Wiring: Rated for 120/208/240 Vac, making it compatible with most commercial and industrial power supplies.
• Precision Sensing: Liquid-filled 12" capillary ensures consistent response times and minimizes calibration drift.
• Safety Configuration: The Open on Rise switch action serves as an essential cutout to prevent overheating in critical equipment.
• Rugged Construction: Features a heavy-gauge steel NEMA 1 enclosure with a gray baked enamel finish for long-term durability.

Can the A19AAB-40 be used for cooling applications?
No. This specific model is SPST Open on Rise, meaning it breaks the circuit when the temperature hits the set point. For cooling or refrigeration where you need to close the circuit on a temperature rise, you would require an Open on Low model or an SPDT version like the A19ABC series.

What is the maximum bulb temperature this unit can handle?
The sensing bulb for the A19AAB-40 is typically rated for a maximum override temperature of 290?F (143?C). Exceeding this limit can cause permanent damage to the volatile liquid charge inside the capillary.

Does this thermostat require a separate power source?
As a mechanical remote bulb control, the A19AAB-40 does not require external power to sense temperature; however, it must be wired into your line-voltage circuit to switch the load (120V to 240V).

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.