A19ADB-38C Johnson Controls Temperature Control

Overview

The Johnson Controls A19ADB-38C is a single-stage mechanical temperature control designed for heating, cooling, and general-purpose HVAC/R applications. Utilizing a remote liquid-filled sensing bulb and a capillary tube, this controller provides reliable high-limit protection by opening the circuit on a temperature rise. Because it features a manual reset mechanism, it ensures deliberate user intervention and acknowledgment before restarting, making it highly suitable for safety-critical installations where automatic resets could mask underlying system issues.

Features

• Manual reset operation ensures safe oversight by preventing automatic restarts after a high-limit trip.
• Remote bulb sensing allows the controller to be mounted separately from the area being monitored.
• SPST (Single-Pole Single-Throw) switch configuration specifically designed to open on temperature rise.
• Dust-protected enclosure with field-proven, snap-acting contacts for high dependability.
• Repeat accuracy that remains completely unaffected by cross-ambient temperatures or barometric pressure fluctuations.
• Convenient screwdriver slot adjustment for setting temperature limits.

Specifications

• Manufacturer Part Number: A19ADB-38C
• Control Type: Remote Bulb Temperature Controller
• Switch Action: SPST, Opens on High (Open High)
• Setpoint Temperature Range: 100°F to 240°F (38°C to 116°C)
• Maximum Bulb Temperature: 290°F (143°C)
• Bulb Dimensions: 3/8 inch diameter x 4 inches length
• Capillary Length: 6 feet
• Electrical Ratings: 24 to 600 VAC; 10A resistive at 120V, 8A resistive at 240V

Applications

• High-limit safety monitoring in commercial and industrial heating systems.
• Temperature regulation and protection in industrial process piping, commercial boilers, and hot water loops.
• Environmental monitoring in commercial HVAC, walk-in refrigeration units, and cooling systems where a safe manual reset is required.
• Air-side and liquid immersion applications requiring precise temperature tracking separate from the control enclosure panel.