Johnson Controls A19ADB-31 Thermostat

The Johnson Controls A19ADB-31 is a heavy-duty, single-stage utility thermostat designed for high-limit applications where a manual reset is required for safety and system protection. This high temperature limit control features a wide setpoint range of 90°F to 325°F, making it a reliable choice for commercial water heaters and industrial processing equipment. Built with a SPST switch that opens on a temperature rise, the unit ensures positive circuit interruption until manually reactivated. The 10-foot copper capillary and 0.29" x 2.5" remote bulb provide flexible mounting options, while the included thermowell protects the sensing element in fluid-immersion applications. Rated for 120/208/240 VAC, the A19ADB-31 is engineered for electrical compatibility across standard HVACR power configurations. This model features an enclosed setpoint adjustment to prevent unauthorized tampering and is functionally identical to the A19ADB-31C, providing a rugged solution for high-ambient thermal monitoring.

Key Benefits for Your Installation:

• Precision Thermal Sensing: Includes a liquid-filled sensing element for consistent response times in critical HVAC temperature control scenarios.
• Safe Manual Overide: The trip-free manual reset mechanism ensures the system cannot be restarted until the high-limit condition is corrected and manually acknowledged.
• Durable Enclosure: Housed in a NEMA 1 industrial temperature controller casing suitable for demanding mechanical room environments.
• Broad Application Range: Optimized for industrial HVAC parts replacement in boilers, tanks, and heat exchangers requiring high-limit cut-out.
• Seamless Integration: The 10' capillary length allows for remote mounting away from the heat source, reducing electronic wear.

Common Technical Questions

Can the A19ADB-31 be used for cooling applications?
No, this unit is designed with an Open High contact structure, meaning it breaks the circuit on temperature rise. It is primarily used as a safety limit switch for heating equipment.

What is the difference between the A19ADB-31 and the A19ADB-31C?
These units are identical in technical specification and performance; the "C" suffix typically denotes Johnson Controls bulk packaging or specific distributor regional labeling.

Does this thermostat require a specific mounting position?
The remote bulb can be mounted in any position via the immersion well, though the controller case should be mounted vertically to ensure easy access to the manual reset button.

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.