Inspects screws, bolts, rivets, welds; brazes parts to assemble structural and functional components such as motors, controls, switches, gauges, wiring harnesses, valves, pumps, compressors, condensers, cores, and pipes. Starts system, observes operation, reads gauges, and instruments, and adjusts mechanisms such as valves, controls, and pumps to control levels of fluid, pressure, and temperature in system.