Audel HVAC Fundamentals Volume 3 Air-Conditioning, Heat Pumps, and Distribution Systems

The controls section of this book needs to be updated, but 90% of the book is still relevant. The text tends to lag behind the images, but this book is packed with a ton of helpful information and plenty of pictures. If you're a mechanic and you're working with older equipment, maybe this book is exactly what you're looking for. This is the second book that I bought by Mr. Brumbaugh, and I noticed there's a little over lapping, but still, this book is a few bucks and what you'll get out of it is worth it.