4 Auto Heating & Air Conditioning
How to Use the Color Key
Colors are used throughout Auto Heating & Air Conditioning to help show different refrigerant states. Other colors are
used to illustrate nonrefrigerant liquids and gases, as well as electrical, mechanical, and special components. The following
key shows what each color represents.
Refrigerant States
High-pressure Liquid Low-pressure Liquid
High-pressure Gas/Vapor Low-pressure Gas/Vapor
Components
Evaporator, Heater core, Condenser, Radiator
Compressor
Accumulator/Receiver-drier
Metering devices, Orifi ce tubes, Thermostats, Expansion valves
Electrical
Electrical-Computer
Supplemental Restraint System (SRS)/Air bag
Airfl ow
Hot air Outside air
Cold air Recirculated air
Blended air
Nonrefrigerant Liquids and Gases
Engine coolant Nonrefrigerant gas, Engine vacuum
Refrigerant oil
Other
Special features or components not otherwise coded.
Copyright by Goodheart-Willcox Co., Inc.