John Tomczyk received his associate's degree in refrigeration, heating, and air-conditioning technology from Ferris State University in Big Rapids, Michigan; his bachelor's degree in mechanical engineering from Michigan State University in East Lansing, Michigan; and his master's degree in education from Ferris State University. Mr. Tomczyk has worked in refrigeration, heating, and air conditioning service and technical writing consultation for both the academic and industrial fields for numerous years -- enabling him to bring a wealth of experience to this text. His technical articles have been featured in many HVACR magazines and journals. Mr. Tomczyk is also the author of TROUBLESHOOTING AND SERVICING MODERN AIR CONDITIONING AND REFRIGERATION SYSTEMS. Mr. Tomczyk has 29 years of teaching experience at the Refrigeration, Heating, and Air-Conditioning Technology program at Ferris State University and is a member of many HVAC/R trade organizations.