Johnson Controls A70HA-14 Temperature Control

The Johnson Controls A70HA-14 Temperature Control is a heavy-duty low-limit freeze stat designed for critical refrigeration and heating applications. This four-wire, two-circuit control features a single-pole, double-throw (SPDT) equivalent switching action where the main contacts open on a temperature drop (Open Low) while the reverse-acting auxiliary contact simultaneously closes to trigger an external alarm or BAS signal. Built with a 20-foot vapor-pressure capillary, it ensures accurate average temperature sensing across large coils, making it a reliable manual reset temperature switch for preventing evaporator freeze-ups. This industrial-grade unit operating at 120-240 Vac includes a trip-free manual reset lockout, ensuring the system remains offline until a technician inspects the fault. The A70HA-14 is functionally identical to the A70HA-14C, providing a rugged NEMA 1 enclosure with a 1/2-inch conduit opening for secure field wiring. Use this HVAC temperature limit control to protect high-value air handling units and chillers from sub-freezing discharge air conditions.

Key Benefits

• Dual-Circuit Logic: Provides simultaneous main load shedding and auxiliary alarm activation for comprehensive system protection.
• Extended Sensing Range: The 20' capillary length allows for effective coil freeze protection by monitoring air temperature trends across broad surfaces.
• Failsafe Security: Features a manual reset lockout that prevents automatic equipment cycling under fault conditions, requiring professional intervention.
• Versatile Compatibility: Rated for 120-240 Vac, fitting standard commercial HVACR electrical profiles.
• Drop-in Replacement: Directly replaces and is identical to A70HA-14C, maintaining original mounting footprints and wiring logic.

Common Questions

How do I wire the auxiliary contact for a remote alarm?
The reverse-acting auxiliary contact (Line to M1) closes when the main contact (Line to M2) opens on a temperature drop. Connect your alarm circuit to the auxiliary terminals to receive an immediate notification upon a low-limit trip.

Can this control be used for high-temperature cutout?
No, the A70HA-14 is an "Open Low" device specifically calibrated for low-limit freeze detection. For high-temperature cutout applications, an "Open High" model from the A70 series is required.

What is the reset procedure after a lockout?
Once the sensed temperature rises approximately 5°F above the setpoint, the "trip-free" manual reset button on the cover must be pressed and released to re-engage the main contacts and clear the alarm circuit.

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.