Hot Air Furnace Circuit Board Control Center
Newer hot-air furnaces feature printed circuit control. The board shown in Fig. 2-8 is such that it is easy for the technician installing the furnace to hook it up properly for the first time. The markings are designed for making it easy to connect the furnace for accessories, if needed. Figures 2-9 and 2-10 show the factory-furnished schematic. See if you can trace the schematic and locate the various points on the printed circuit boards.