A70HA-1C Johnson Controls Temperature Control

Overview

The Johnson Controls A70HA-1C is a heavy-duty, manual reset mechanical temperature control designed for HVAC and refrigeration systems. It features a vapor-charged sensing element with a 4-wire, 2-circuit contact block containing two isolated sets of contacts engineered to transfer simultaneously at the setpoint, providing reliable system protection.

Features

• Long-life contact structure with high contact force right up to break to eliminate contact bounce on make.
• Manual reset lockout design is trip-free, requiring physical intervention before restarting after a temperature deviation.
• Dual-circuit, two-pole construction allows the auxiliary contact to actuate an alarm circuit or indicator light simultaneously when the main contact opens.
• Heavy-gauge, low-profile stainless steel element cup provides robust protection against mechanical damage.

Specifications

• Temperature Range: 15°F to 55°F
• Differential: 5°F Fixed
• Main Contact Action: Open Low (opens on temperature drop)
• Capillary Length: 20 feet (240 inches) with a 1/8-inch bulb diameter
• Voltage Rating: 120 to 600 VAC (Main), 120 to 300 VDC (Auxiliary)
• Maximum Temperature Rating: 400°F
• Enclosure Material: Cold-rolled steel housing with a gray finish
• Conduit Opening: 1/2 inch

Applications

• High-reliability low-limit freeze protection and thermal shutdown for commercial ventilation systems.
• BAS alarm indication and safety cutout for commercial HVAC and refrigeration systems.
• Walk-in coolers, freezers, and industrial heating applications requiring manual reset safety protection.