As a secret service man who is also an HVAC technician on the side, I have had a lot of exciting things happen in my life that involves HVAC units.
I can think of one time specifically when I was in an air conditioner and furnace warehouse where there were stored thousands of central air conditioners, window air conditioners, furnaces of every kind, and air purifiers, and it was my mission to find a specific central air conditioner that had a bomb implanted in it. I had two other workers with me who were FBI agents, but I was the only one with an extensive HVAC knowledge, so when we found the central air conditioner, it was my responsibility to disarm the bomb without setting it off in the air conditioner. Finding this central air conditioner proved to be extremely difficult since the warehouse was so huge and there were literally central air conditioners of every kind on every shelf and in every section of the warehouse. Luckily I had some knowledge of house moste HVAC warehouses were set up since I had helped organize one a long time ago when I had first become an HVAC technician, so I had a little bit of an advantage for finding this mysterious central air conditioner. When we found the central air conditioner, we carefully took it apart and I began working on the bomb wires which were connected to the central air conditioner wires. After many hours of work, I had the bomb disarmed and we saved the HVAC warehouse. Being an HVAC technician and a secret service man is thrilling.