A11B-1C Johnson Controls AUTO RESet

Overview

The Johnson Controls A11B-1C is a high-performance electromechanical low-temperature cutout control designed to protect commercial HVAC systems and hydronic components from freezing conditions. It features a vapor-charged sensing element that detects the coldest localized temperatures along its length. When temperatures drop below the setpoint, the switch opens to disrupt system operations and automatically closes (resets) once temperatures rise safely back above the differential.

Features

• Automatic reset functionality that recycles the control automatically when temperatures rise
• Snap-acting SPST switch configuration housed within a dust-protected enclosure
• Clear external temperature scale for straightforward visual confirmation of system settings
• Easy setpoint adjustment using a standard screwdriver slot accessible at the bottom or top of the unit
• Galvanized steel case, cover, and standard mounting brackets for durable commercial installation

Specifications

• Temperature Range: 35 to 45°F (2 to 7°C) adjustable cutout range
• Fixed Differential: 12°F (6.7°C)
• Sensing Element: 1/8 in. x 20 ft vapor-filled capillary sensing bulb with a 4 ft capillary lead
• Switch Action: SPST, opens on temperature fall (Open Low)
• Electrical Rating: 16.0 A full load at 120 VAC; 9.2 A at 208 VAC; 8.0 A at 240 VAC; 125 VA pilot duty (24 to 277 VAC)
• Enclosure Materials: 0.6 in. cold rolled steel case and 0.3 in. cold rolled steel cover with galvanized finish
• Ambient Temperature Limits: 0 to 140°F (-18 to 60°C) for the control enclosure
• Maximum Element Temperature: 250°F (121°C)

Applications

• Monitoring the face temperature of hydronic coils, cooling coils, and evaporator coils for freeze protection
• Detecting low-temperature conditions in liquid handling pipes to prevent icing and subsequent structural damage
• Integration with Building Automation Systems (BAS) and commercial HVAC air-side monitoring applications