Reznor CAUA is a gas-fired upflow heater designed for use in air turnover applications. It features an optional mounting base with guarded openings on all four sides, allowing for return air circulation. The base can be used with an optional discharge plenum to create a "packaged stand-alone" heating or heating/cooling system. It has a range of sizes and can be used with various filter options. Installation requires a fairly open area with three or four sides open to ensure proper airflow. Leveling the base before placing the heater on top is crucial for optimal performance.