Purdy-McGuire designed the original MEP systems for Dallas' tallest building in 1983. Some 30 years later, we had the privilege to design the central plant equipment replacement and associated building automation upgrades. The replacement project consisted of three 1,300 low-temperature chillers in series, three chilled water, and three condenser water pumps. Due to physical limitations, each chiller had to be shipped in three components and reassembled in place. The new central plant upgrades achieved zero downtime for the office tower air conditioning systems, and energy usage has been reduced by 14%.