Old Trane Climate Changer Air Handlers

Looking at some old Trane Climate Changer Air Handlers in a middle school. These units are from 1979 (40 years old!) and are original to the building. Everything was originally controlled by pneumatic, they were retrofitted with Tracer Summit DDC several years ago. The building is now under renovation and all of these units will be demolished over the next several years. You can't stop a Trane!