Rooftop Model RDH has been added to the indoor, pre-engineered ventilation air handlers (PREEVA® Series). This equipment includes both power-vented and separated combustion indoor models from 75,000-to 400,000-Btuh gas heating capacity, and 565 to 7,500 cfm airflow. Model RDH has modular add-on cabinets for advanced direct expansion (DX) or chilled-water cooling, mixed air control, evaporative cooling, and high-performance filtering. The series utilizes the highly efficient TCORE2® combustion system as the "heat engine" for the units and has both analog and digital controls.