Diagnose, assess, and troubleshoot various types of HVAC equipment, including but not limited to Chillers, Boilers, Air Handlers, large (over 20 ton) Rooftop Units, Split Systems, Water-Source Heat Pumps, Pumps and miscellaneous plant equipment. Performs disassembly and reassembly of large or small commercial HVAC equipment to perform troubleshooting and planned maintenance as indicated in the service agreement.