I'm late to this thread but I have to ask Delta. I worked in the DC area in the eighties, mostly servicing JCI systems (Naval Academy, National Archives, etc). But I do remember an old HW Delta 1000(?) system at George Washington University. You had to use a tape recorder to reload the CPU! The front end is probably gone but the field panels were rock solid (albeit unwieldy to work on). Hadn't thought about those days in a long time.
BTW - The National Archives had a JC85/40 system monitoring and running the chiller but the rest was all pneumatics. Keeping that old system (and building, and equipment) calibrated for temperature AND humidity control was a b*tch - but it's where I learned pneumatics and HVAC. Something that many HVAC engineers and controls types could take a lesson from.