The Rheem-Ruud RTG20239CX Control Board is an electronic component designed to regulate and coordinate the operation of Rheem and Ruud HVAC systems, including furnaces and packaged heating units. It functions by processing input signals from sensors and thermostats to control ignition, blower motors, and safety circuits, ensuring precise system performance. https://www.partshnc.com/rtg20239cx-rheem-ruud-control-board