1. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Chapter 12 Air Delivery Systems

2. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. l. Objectives  Explain how an HVAC system blower operates.  Identify the major parts of an HVAC system blower and motor.  Explain the operation of HVAC blower speed controls.

3. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. ll. Objectives  Identify the purposes of HVAC system air ducts.  Explain the design and placement of HVAC system air ducts.  Identify the types and purposes of HVAC system air doors.

4. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. lll. Objectives  Explain how HVAC system air doors are operated.  Identify and explain HVAC system air door operating devices.

5. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Air Handling Systems

6. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Air Handling System Air Handling System Functions  Generates airflow  Ensures air is heated or cooled as necessary  Delivers air to proper place in passenger compartment

7. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Note  Some of the most common problems affecting the HVAC system are caused by defects in the blower, ductwork, and air doors.

8. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Air Handling System Components  Blower wheels Blower wheels  Blower motors Blower motors

9. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Upstream / Downstream  Refers to position of a component in air delivery system as compared to any other component  Upstream receives incoming air before another component Upstream  Downstream receives incoming air after another component Downstream

10. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Rear Heating / Cooling  Rear heating / cooling systems may have a second blower and motor located at rear of passenger compartment

11. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Blower Wheel  The blower fan consists of a blower wheel (squirrel cage blower)squirrel cage blower

12. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Blower Wheel  Centrifugal air pump  Blades are shaped so rotating wheel pulls air into its center and drives it outward

13. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Blower Wheel Illustration Power lead Ground lead Motor Blower wheel

14. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Blower Motor  Connected to the electrical system through ignition switch and HVAC controls  Some have a shaft at each end, and turn two blower wheels

15. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Blower Motor Illustration

16. Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc. Blower Motor (Cont.)  Usually vented to cool windings  Must turn in proper direction  Fan blades must be pointed in proper direction