Schematic Diagrams for HVAC Systems: What You - Modernize Schematic Diagrams for HVAC Systems: What You Need to Know. Inside those compact units are electrical connections, fans, compressors, condensors, switches, coolants—the list goes on and on. And not every unit is built the same way. AC and heating units are kind of like cars—they share most of the same components,.. BASIC ELECTRICITY FOR HVACR TECHNICIANS | Contracting Business BASIC ELECTRICITY FOR HVACR TECHNICIANS. A typical schematic of a packaged air conditioner is shown in Figure 1. In electrical schematics, the symbols stand for various components in the circuit, and the lines stand for the wires connecting them. The intention of the overall schematic is to show how the circuit functions,..