Knowledge of methods, materials, tools and equipment used in the installation, repair and maintenance of refrigeration, chilling, air-conditioning and heating equipment up to 550 tons in capacity, including absorption chillers, pumps, condensers, heat exchangers, cooling towers, reciprocating, centrifugal and screw type compressors, thermostats, electrical, pneumatic and PLC and micro-processor based controls. Installs, repairs and maintains pumps, air compressors, steam and hot water boilers, heating and boiler tubes, heat exchangers, fans, dampers, hydraulic units, control and monitoring systems.