Performs or assists in the performance of the following: rebuilding pumps and compressors, replacing bearings and seals, repairing or replacing plumbing systems or components, installing threaded or sweated pipe segments, repairing or replacing refrigeration components, and performing maintenance of installed irrigation systems . Such work includes, but is not limited to, HVAC, electrical, plumbing, pipefitting, kitchen equipment, hot-water generation equipment, refrigeration equipment, machine tools, and motor and control systems.