Demonstrates skills in the use (and interpretation of acquired information) of test equipment used in the troubleshooting, repair and maintenance of building systems, and plant equipment (i.e., temperature and humidity recorders, ground fault testers, infrared devices, isolation power tester, voltage recorder, etc.). Demonstrates advanced knowledge and skills in the design, troubleshooting and repair of air conditioning and refrigeration systems and equipment, (i.e. BTU calculations, Liebert units, chiller operation, cooling towers capacity, roof top chillers, and walk-in freezers).