Johnson Controls A19QSC-1 Temperature Control

The Johnson Controls A19QSC-1 is a commercial-grade, remote bulb temperature control designed for demanding environments. This mechanical temperature control features a single-pole, double-throw (SPDT) switch configuration, providing versatile heating and cooling application support. Built with a NEMA 4X watertight enclosure, the A19QSC-1 offers superior protection against corrosion and moisture, making it ideal for cooling tower sump heaters and agricultural ventilation. This unit is the direct replacement for A19KNC-1, ensuring a seamless fit for legacy systems. It operates across a wide electrical range from 24 to 277Vac and includes an automatic reset for reliable, unattended performance. The 0 to 150 degree F setpoint range and 5 degree F fixed differential are managed via a concealed screwdriver slot range adjuster, preventing unauthorized tampering while maintaining surgical precision through its 10' capillary and 3/10" x 2 1/2" sensing bulb. For contractors requiring a rugged industrial thermostat, the PENN A19 series remains the standard for durability.

Key Benefits

• NEMA 4X Enclosure: High-impact thermoplastic housing provides a watertight, dusttight, and corrosion-resistant seal for indoor and outdoor use.
• Legacy Compatibility: Designed as the official replacement for A19KNC-1, streamlining maintenance on existing HVACR installations.
• Concealed Calibration: The internal screwdriver slot range adjuster prevents accidental setpoint shifts in high-traffic commercial areas.
• SPDT Switching: Multi-functional internal switch allows for both heating control and cooling tower sump heater management.
• Industrial Durability: Incorporates a liquid-filled remote sensing bulb and 10-foot capillary for consistent response in volatile thermal environments.

Common Questions

How do I wire the A19QSC-1 for cooling versus heating?
On this SPDT control, use the Red and Yellow terminals for cooling applications (closes on temperature rise) and the Red and Blue terminals for heating (opens on temperature rise). Always verify the current draw against the 24 to 277Vac electrical ratings in the field.

What are the primary applications for a NEMA 4X temperature control?
The Johnson Controls A19QSC-1 is typically deployed in wash-down areas, cooling tower installations, food processing plants, and livestock ventilation systems where moisture and corrosive agents would compromise standard controls.

Can the 5 degree fixed differential be adjusted?
No, the A19QSC-1 features a fixed 5 degree F differential. If your application requires an adjustable deadband, consider the A19ABC or A19AAF series depending on the required setpoint range.

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.