This 78-page book provides a comprehensive overview of the heat pump system, it¿s operations and principles. The heat pumps covered in this book are basic systems. The intent of the book is to offer technicians information to build upon to enhance their knowledge of the air conditioning and heating field, specifically, heat pumps. Before installing or servicing a heat pump system, the technician must have proper training and knowledge of air conditioning/refrigeration theory, principles and operation. New highly efficient equipment heat pump systems using HFC refrigerant (R-410A) are being sold and installed. These systems pose new demands for installers and service technicians. A heat pump¿s efficiency can be greatly diminished, regardless of the type of refrigerant, if it is not properly installed, serviced and maintained.