Johnson Controls A70BA-18 Temperature Control

The Johnson Controls A70BA-18 Temperature Control is a heavy-duty low limit freeze protection thermostat engineered for critical refrigeration and heating applications. Designed with a single pole, single throw (SPST) contact structure, this "Open Low" control is specifically built to protect HVAC coils from freezing by opening the circuit when the sensed temperature drops to the user-defined setpoint. With a temperature range of 15°F to 55°F and a fixed 5°F differential, it provides precise freeze stat monitoring in air handling units and cold storage environments. The 20-foot capillary length allows for extensive coverage across a coil face, ensuring the vapor-charged sensing element detects the coldest spot effectively. For elevated system safety, the A70BA-18 features a lockout with manual reset, preventing the equipment from restarting automatically after a low-temperature trip until a technician inspects the system. This 120-240 Vac unit includes a 1/2" conduit opening and a rugged NEMA 1 enclosure for reliable field installation.

Key Benefits

• Vapor-Charged Sensing: The 20' sensing bulb is spot-sensitive, reacting to the coldest section along the capillary for superior HVAC coil protection.
• Manual Reset Lockout: Ensures manual intervention is required after a trip, preventing short-cycling or damage in "Open Low" conditions.
• Universal Voltage Compatibility: Rated for 120-240 Vac, making it a versatile choice for a wide variety of commercial refrigeration and heating systems.
• Industrial Build: Features a snap-acting contact structure with high contact force to eliminate bounce and ensure long-term electrical reliability.
• Flexible Installation: Integrated 1/2 inch conduit opening and standard mounting holes facilitate easy integration into existing control panels.

Common Questions

What is the difference between an A70AA and an A70BA model?
The A70AA is an automatic reset model, while the Johnson Controls A70BA-18 is a manual reset model. The manual reset is "trip-free," meaning it cannot be bypassed by holding the button down, ensuring the safety protocol is followed.

Can this be used for both heating and refrigeration?
Yes, it is designed for both refrigeration and heating. Most commonly, it is utilized as a freeze protection thermostat in HVAC air handlers to shut down fans or open heating valves when temperatures drop too low.

Does the sensed temperature need to rise before I can reset it?
Yes. For the A70BA-18, the temperature must rise at least 5°F above the cutout setpoint before the manual reset button will engage and restore the circuit.

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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.