Maintain, repair, and replace air-moving, heating, cooling, humidification, and filtering equipment and systems, such as fans, heat pumps, fan coil units, rooftop package air conditioning units, computer room cooling units, electronic and pneumatic modulating thermostats, humidistats, duct stats, and pressure and volume controls. Maintain, repair, and replace air conditioning equipment of the reciprocating and centrifugal types, including related electrical motors and their respective controls, calibration of equipment, gauges, and controls, handling of refrigerant, and refrigerant charging of systems.