A19ADB-2C Johnson Controls Temperature Control

Overview

The Johnson Controls A19ADB-2C is a line-voltage mechanical temperature control designed for direct well immersion applications in commercial and hydronic heating systems. Featuring a liquid-filled sensing element, this single-stage controller delivers rapid and accurate responses to temperature variations. It includes a high-temperature lockout mechanism with a manual reset function, ensuring the system shuts down safely upon reaching a high-temperature limit and requires user intervention to resume operation.

Features

• Liquid-filled sensing element provides fast and dependable response to temperature changes
• Manual reset action locks out at high temperatures, preventing automatic resumption for enhanced safety
• Equipped with a standard knob range adjuster for easy temperature setting modifications
• Rugged NEMA 1 enclosure protects internal components against dust and physical tampering
• Complete with a 1/2-inch NPT well connector assembly for direct immersion installation

Specifications

• Temperature Control Range: 100°F to 240°F (38°C to 116°C)
• Switch Type: Single-Pole, Single-Throw (SPST)
• Switch Action: Open on temperature rise (Open High with lockout)
• Maximum Bulb Temperature: 250°F (121°C)
• Electrical Ratings: 120 VAC (10.0 FLA, 60.0 LRA); 240 VAC (6.0 FLA, 36.0 LRA)
• Pilot Duty Rating: 125 VA at 24 to 600 VAC
• Enclosure Rating: NEMA 1
• Well Connection Size: 1/2-inch NPT

Applications

• Designed primarily as a high-limit cutout or operating control for hot water boilers and hydronic heating systems
• Suitable for universal replacement applications requiring single-stage temperature control with lockout safety functionality
• Utilized in industrial and commercial HVAC systems where direct fluid immersion monitoring is necessary