Book excerpt: When installing or servicing an air conditioning or refrigeration system, two of the most important tasks performed by technicians are refrigerant recovery and system evacuation. In order to perform these tasks properly, and in a safe manner, technicians need to understand the theory behind them, having a working knowledge of the equipment and tools used, and employ accepted industry best practices. This e-book walks through each step of both tasks, while covering safety, theory, and application. Also covered are leak detection methods and filter drier use. System Recovery and Evacuation was written by HVACR instructors for HVACR instructors to provide sound, relevant information in a single source. This e-book provides students and practicing technicians with the information and knowledge necessary to understand refrigerant recovery, system evacuation, leak detection, and filter driers. It is full of color illustrations and includes worksheets that provide students and practicing technicians with the information and knowledge necessary to accurately and safely install or service air conditioning and refrigeration systems. The end of the e-book contains fill-in-the-blank questions that review the content of the entire manual.