1. HVAC Wiring
Understanding Wiring

2. HVAC Wiring
Wiring diagrams are road maps for electron flow

3. HVAC Wiring HVAC Technicians must know: How to draw them
How to read them

4. HVAC Wiring
Drawing diagrams
Begin with a description of how the circuit is too work
Draw a diagram a main single pole/single throw switch that controls all loads. A single pole/single throw switch controlling a 60w bulb. A single pole/single throw switch controlling two 40w bulbs connected in parallel. A single pole/double throw switch controlling a 40w bulb in one position and two 60w bulbs wired in series controlled when the single pole/double throw switch is in the other position.

5. HVAC Wiring
Drawing diagrams
Next Create a Written flow chart

6. HVAC Wiring Drawing diagrams
Use the flow chart to complete a Ladder Diagram
Place the switch that controls everything of L1

7. HVAC Wiring Drawing diagrams
Using the flow chart add a circuit that add a branch circuit
Place a spst switch in series with a 60w bulb

8. HVAC Wiring Drawing diagrams
Use the flow chart to complete a Ladder Diagram
Now place the next switch in the circuit

9. HVAC Wiring Drawing diagrams
Use the flow chart to complete a Ladder Diagram
Place the bulbs controlled by the switch in the circuit

10. HVAC Wiring Drawing diagrams
Use the flow chart to complete a Ladder Diagram
Complete the ladder with the last circuit

11. HVAC Wiring Drawing diagrams
Use the Ladder Diagram to wire the project board
Wire one branch at a time

12. HVAC Wiring Drawing diagrams
Note how since L1 power has been brought to SW1 that is where we can pick up power for the next switch

13. HVAC Wiring Drawing diagrams
Note how since N or L2 has been brought to Bulb 1 we use any terminal that has a direct line back to N/L2 as a connection to N/L2

14. HVAC Wiring
Drawing diagrams
Complete project

15. HVAC Wiring
Drawing diagrams
Note alternate L1 connections