The Johnson Controls A19ABC-11 is a robust mechanical temperature control designed for demanding hot water immersion applications. This SPDT temperature switch features a liquid-filled sensing element that ensures rapid response to temperature fluctuations, making it an ideal operating control for hot water boilers and general-purpose heating systems. The unit operates across a 100 to 240 degree F setpoint range with an adjustable differential of 6 to 24 degrees F, allowing technicians to fine-tune system cycles for optimal efficiency. Engineered for versatility, it supports 24 to 277Vac electrical ratings and provides Open High (R-B) or Opens Low (R-Y) switching logic. The automatic reset functionality ensures consistent performance without manual intervention. This direct replacement for 433 and A19ABC-11C comes standard with a 1/2" NPT well connector and a convertible range adjuster, facilitating seamless integration into existing hydronic piping. Whether you are performing a universal replacement or a new installation, this industrial-grade thermostat offers the precision and repeat accuracy required by professional HVACR contractors. Key Benefits Universal Compatibility: Serves as a direct replacement for Johnson Controls 433 and A19ABC-11C models. Fast Thermal Response: The liquid-filled element provides high-speed sensing for precise boiler water temperature management. Flexible Adjustment: Features a convertible range adjuster for knob, internal, or external screwdriver slot settings. Industrial Durability: Housed in a NEMA 1 enclosure with dust-tight, snap-acting contacts to ensure long-term reliability in mechanical rooms. Wide Voltage Range: Rated for 24V to 277V, making it suitable for a variety of commercial and residential control circuits. Common Questions How do I wire the A19ABC-11 for heating vs. cooling? For heating (open high), use terminals Red (Common) and Blue. For cooling or low-limit applications (open low), use terminals Red (Common) and Yellow. Can the differential be adjusted while the system is live? While physically possible, it is professional best practice to disconnect power before removing the cover to adjust the 6 to 24 degree F differential lever. Does this include the immersion well? Yes, the A19ABC-11 is furnished with a 1/2" NPT well assembly for direct immersion in tanks or piping. 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.
