Mazda Training manual — part 256

Air Conditioning Fundamentals

TC070-05-01S

CONTENTS

page ii

4 –PRINCIPLES OF REFRIGERATION
Objectives . . . . . . . . . . . . . . . . . . . . . . ... 16
Six Principles . . . . . . . . . . . . . . . . . . . . . .. 16

Principle One: Heat Transfer . . . . . . . . . . . . . ... 17
Principle Two: Temperature and Mass . . . . . . . . . . . 18
Principle Three: Latent Heat of Vaporization. . . . . . . . 18
Principle Four: Latent Heat of Condensation . . . . . . . ... 20
Principle Five: Pressure and Boiling Point . . . . . . . . ... 21
Principle Six: Compressed Vapor . . . . . . . . . . . . 22

Review Exercise 3 . . . . . . . . . . . . . . . . . . . .. 23

5–AIR CONDITIONING COMPONENTS
Objectives . . . . . . . . . . . . . . . . . . . . . . ... 24
Overview. . . . . . . . . . . . . . . . . . . . . . . . 25
Compressor . . . . . . . . . . . . . . . . . . . . . . 26

Axial (Piston-Type) Compressors . . . . . . . . . . . . 27
Vane (Non-Piston-Type) Compressors . . . . . . . . . . 29

Condensor . . . . . . . . . . . . . . . . . . . . . . .. 31
Review Exercise 4 . . . . . . . . . . . . . . . . . . . .. 32
Receiver / Dryer . . . . . . . . . . . . . . . . . . . . .. 33
Expansion Valve / Orifice Tube . . . . . . . . . . . . . . ... 34

Expansion Valve . . . . . . . . . . . . . . . . . . .. 34
Orifice Tube . . . . . . . . . . . . . . . . . . . . . 35

Evaporator . . . . . . . . . . . . . . . . . . . . . . .. 36
Accumulator. . . . . . . . . . . . . . . . . . . . . . 37
Review Exercise 5 . . . . . . . . . . . . . . . . . . . .. 39

6 – REFRIGERATION CYCLE
Objectives . . . . . . . . . . . . . . . . . . . . . . ... 40
Stages of the Refrigeration Cycle . . . . . . . . . . . . . ... 40

Overview. . . . . . . . . . . . . . . . . . . . . .. 40
High Pressure . . . . . . . . . . . . . . . . . . . .. 42
Condensation . . . . . . . . . . . . . . . . . . . .. 43
Pressure Reduction . . . . . . . . . . . . . . . . . . 44
Evaporation . . . . . . . . . . . . . . . . . . . . . 45
Orifice Tube System . . . . . . . . . . . . . . . . . 46

Review Exercise 6 . . . . . . . . . . . . . . . . . . . .. 47

Air Conditioning Fundamentals

TC070-05-01S

CONTENTS

page iii

7 – REFRIGERANTS
Objectives . . . . . . . . . . . . . . . . . . . . . . ... 48
Introduction to Refrigerants. . . . . . . . . . . . . . . . . 48
CFC-12 (R-12) . . . . . . . . . . . . . . . . . . . . . 49

Chemical Structure . . . . . . . . . . . . . . . . . .. 49
Properties of R-12. . . . . . . . . . . . . . . . . . 49

HFC134a (R-134a) . . . . . . . . . . . . . . . . . . . . 50

Chemical Structure . . . . . . . . . . . . . . . . . .. 50
Properties of R-134a. . . . . . . . . . . . . . . . . 51

Differences Between Refrigerants . . . . . . . . . . . . . .. 51
Recycled, Reclaimed, and Extracted Refrigerant . . . . . . . ... 52

Recycled Refrigerant . . . . . . . . . . . . . . . . ... 52
Reclaimed Refigerant . . . . . . . . . . . . . . . . .. 52
Extracted Refrigerant. . . . . . . . . . . . . . . . ... 53

Storing Recycled Refrigerant . . . . . . . . . . . . . . . .. 53
Retrofitting . . . . . . . . . . . . . . . . . . . . . . .. 55

“Drop-In” Replacement Refrigerants for R-12 . . . . . . . .. 55
Retrofitting System Components . . . . . . . . . . . . . 55

Safety Procedures . . . . . . . . . . . . . . . . . . . .. 56
Review Exercise 7 . . . . . . . . . . . . . . . . . . . .. 57



8 –AIR CONDITIONING LUBRICANTS
Objectives . . . . . . . . . . . . . . . . . . . . . . ... 58
Refrigeration Lubrication. . . . . . . . . . . . . . . . . . 58

Mineral Oil and PAG Oil . . . . . . . . . . . . . . . ... 58
Characteristics of Refrigeration Oil . . . . . . . . . . . .. 58

Oil Quantity and Component Replacement. . . . . . . . . . . 59
Review Exercise 8 . . . . . . . . . . . . . . . . . . . .. 60



9 – AIR DISCHARGE MANAGEMENT
Objectives . . . . . . . . . . . . . . . . . . . . . . ... 62
Air Flow Management Components. . . . . . . . . . . . . 63

Fresh/ Re-circulated Air Door . . . . . . . . . . . . . .. 64
Blower Fan . . . . . . . . . . . . . . . . . . . . .. 65
Temperature Blend Door. . . . . . . . . . . . . . . .. 66
Defroster Door . . . . . . . . . . . . . . . . . . . . 67
Vent / Face Heater Doors . . . . . . . . . . . . . . . 68

Review Excercise 9 . . . . . . . . . . . . . . . . . . . 69

Air Conditioning Fundamentals

TC070-05-01S

CONTENTS

page iv

10– SERVICING
Objectives . . . . . . . . . . . . . . . . . . . . . . ... 70
Overview. . . . . . . . . . . . . . . . . . . . . . . . 70
Check the Pressure . . . . . . . . . . . . . . . . . . . 71

Manifold Gauge . . . . . . . . . . . . . . . . . . ... 71
Making the Connection . . . . . . . . . . . . . . . . 72
Using Manifold Gauges . . . . . . . . . . . . . . . ... 74
Guidelines. . . . . . . . . . . . . . . . . . . . . 74
Evaluating Gauge Readings . . . . . . . . . . . . . . 74
Refrigerant Stations . . . . . . . . . . . . . . . . . . 75
Recovery . . . . . . . . . . . . . . . . . . . . . . 76
Recycling . . . . . . . . . . . . . . . . . . . . . . 76
Evacuation . . . . . . . . . . . . . . . . . . . . ... 76

Review Exercise 10 . . . . . . . . . . . . . . . . . . . 77
Leak Testing. . . . . . . . . . . . . . . . . . . . . . 78

Large Leaks . . . . . . . . . . . . . . . . . . . . . 78
Small Leaks . . . . . . . . . . . . . . . . . . . . . 78
Electronic Leak Detector. . . . . . . . . . . . . . . .. 79
Dye Test. . . . . . . . . . . . . . . . . . . . . ... 79
Harder to Spot Leaks . . . . . . . . . . . . . . . . ... 80
After Detection . . . . . . . . . . . . . . . . . . . . 80

Review Excercise 11. . . . . . . . . . . . . . . . . . ... 80
Charging the System . . . . . . . . . . . . . . . . . . .. 81
Review Exercise 12 . . . . . . . . . . . . . . . . . . . 81



COURSE SUMMARY
Safety Precautions. . . . . . . . . . . . . . . . . . . .. 82
Physical Laws . . . . . . . . . . . . . . . . . . . . . . 82
A/C System Components. . . . . . . . . . . . . . . . . 82

Compressor . . . . . . . . . . . . . . . . . . . . . 83
Condenser . . . . . . . . . . . . . . . . . . . . ... 83
Receiver / Dryer. . . . . . . . . . . . . . . . . . ... 83
Accumulator. . . . . . . . . . . . . . . . . . . . . 83
Expansion Valve / Orifice Tube . . . . . . . . . . . . . 83
Evaporator . . . . . . . . . . . . . . . . . . . . ... 83

Refrigerants . . . . . . . . . . . . . . . . . . . . . . 84
A/C Servicing . . . . . . . . . . . . . . . . . . . . . .. 84

Air Conditioning Fundamentals

TC070-05-01S

1 – INTRODUCTION

1

COURSE OVERVIEW


Welcome to the Mazda self-study guide, Air Conditioning Fundamentals. Before you begin,
please read the following information.

Audience and Purpose

This guide is designed for entry-level automotive technicians. It introduces the basic
principles of air conditioning (A/C) operation and describes major A/C components.

The guide assumes that you have little or no knowledge about automotive A/C operation.
Mazda requires the information covered in this guide for more advanced A/C courses.