This is a technology that I never really wanted to learn about, but I did it because I had to and I am very glad I did. Back in the early 1980s there was a very bad recession going on. I was working at S&S machinery and machine tool sales dropped from one or two a week down to one every month. Fearing that I would be laid off I took test for all different kinds of government jobs. The Post Office called me first. I wanted to come in as a machinery mechanic on the letter sorting equipment, but at the interview the told me that they really needed guys with an electronics background to work on AC systems. I told them I never had any HVAC systems training or exposure. They told me not to worry because they will train me. All I had to do was bring my electronics know how, and train me they did. Once they saw how high my grades were they just kept on sending me to more schools and I got many promotions along the way. I worked on Centrifical chillers up to 1250 tons four of them in a 6000-ton system and absorption chillers up to 500 tons 2 of them in a 1000-ton system.