Every one here should buy & read this text book. Modern Refrigeration and Air Conditioning. This one is By Andrew D Althouse, Carl H Turnquist & Alfred F Bracciano. It explains the fundamental laws of physics, Like" Energy can not be created or destroyed" we just change its forms. It's about a 1000 pages with diagrams and pictures. There is another one by the same name,,not as informing. A 1980's edition will be talking about R12 & R22. The newer version ( I RECOMEND) is essentially the same but todays refrigerants are used as examples. It covers theory, plus all the basic refrigeration AC, Electrical systems and tools. If you read and Grasp all the fundamentals in this book, you will understand your boat much better. The Laws of Thermodynamics say; Zeroth Law: "You must play the game" First Law: "You can't win" Second Law: "You can't break even" Third Law: You can't quit the game" Do you want to play Thermodynamics ?????? I forgot "you MUST " !!!!!!!!