This book is designed to provide the reader with a comprehensive overview of the heat pump system, its operations and principles. It should be noted that the heat pumps covered in this book are basic systems. The intent of the book is to offer technicians information to build upon, in order to enhance their knowledge of the air conditioning and heating field, and more specifically, heat pumps. Before installing or servicing a het pump system, the technician must have proper training and knowledge of air conditioning/refrigeration theory, principles, and operation.