1. Reading Schematic Diagrams
Electricity for Refrigeration, Heating and Air Conditioning 7th Edition
Chapter 6 Reading Schematic Diagrams

2. Reading Schematic Diagrams
Upon completion of this chapter the student will be able to:
Read and interpret the schematic a dehumidifier
Read and interpret the schematic of a window air conditioner
Read and interpret the schematic of a walk-in-cooler
Read and interpret the schematic of a commercial freezer
Read and interpret the schematic of a gas furnace with a standing pilot
Read and interpret the schematic of a small pack­aged residential air conditioner
Read and interpret the schematics commercial air-conditioning systems with control relays

3. Reading Schematic Diagrams
Upon completion of this chapter the student will be able to:
Read and interpret the schematics commercial air-conditioning systems with lockout relays
Read and interpret the schematics of two-stage heating and two-stage cooling systems
Read and interpret the schematics of heat pumps with defrost boards and defrost timers
Read and interpret the schematic of a commercial refrigeration system with pump down
Read and interpret most diagrams found in the refrigeration, heating, and air-conditioning industry

4. Key Terms Balance Point Combustion Chamber Control Relay Defrost Cycle
Dehumidifier
Gas Furnace
Heat Pump
Light Commercial Air-Conditioning Systems
Limit Switch
Line Voltage Control Systems
Lockout Relay
Low-Voltage Control System
Multistage Thermostat
Pump-down Control System
Set Point
Short Cycle

5. Schematic Diagram Design
The schematic diagram resembles a ladder in that it is made up of two vertical lines representing the incoming electrical sources.
The electrical source is electrical energy being supplied to equipment.
The schematic wiring diagram uses symbols to represent electrical components in the system.

6. Schematic Diagram Design

7. Schematic Diagram Design

8. Schematic Diagram Design

9. Schematic Diagram Design

10. Schematic Diagram Design

11. Schematic Diagram Design

12. Schematic Diagram Design

13. Schematic Diagram Design

14. Schematic Diagram Design