The Johnson Controls A19CAC-1 is a standard-setting mechanical temperature control designed specifically for automatic changeover in fan coil units and convector systems. Engineered for surface mounting, this SPDT changeover control eliminates the need for manual selector switches by automatically sensing media temperature to toggle between heating and cooling modes. It features a 60 to 90?F setpoint range and a 10?F fixed differential, ensuring precise HVAC system performance without frequent cycling. Built with veteran contractors in mind, the A19CAC-1 includes a 42-inch capillary and a remote bulb for flexible strap-on mounting on vertical or horizontal piping. The unit is rated for 24 to 240Vac, making it compatible with a wide array of line voltage and pilot duty applications. A concealed adjustment cover prevents unauthorized setpoint tampering, while the liquid-filled sensing element maintains high repeat accuracy regardless of barometric pressure or ambient enclosure temperatures. Key Benefits Automatic Changeover Logic: Seamlessly switches fan coil operations between heating and cooling based on supply water temperature. Remote Bulb Mounting: The 42" capillary allows for versatile positioning on heavy-duty piping systems using the included strap-on assembly. Contractor-Grade Durability: Features a rugged NEMA 1 enclosure and dust-protected switch mechanism for reliable performance in demanding mechanical rooms. Tamper-Resistant Design: The concealed setpoint adjustment ensures system parameters remain exactly where the technician set them. Common Questions How do I wire the A19CAC-1 for heating and cooling? The SPDT contacts utilize color-coded terminals: the red terminal is common. These contacts close on temperature decrease to signal cooling and open to signal heating at the designated setpoint. Can this control be used for direct immersion? This specific model is optimized for strap-on surface mounting. For immersion applications, ensure the bulb is properly secured to the pipe with high-temperature tape and insulated for accurate sensing. What is the maximum ambient temperature for the case? The A19CAC-1 is designed to operate in ambient environments up to 131?F (55?C), while the sensing bulb can withstand temperatures up to 250?F (121?C). 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.
