23410 HEATING, VENTILATION, AND AIR-CONDITIONING MECHANIC The Heating, Ventilation, and Air-Conditioning Mechanic installs, services and repairs environmental-control systems in residences, department stores, office buildings, and other commercial establishments, utilizing knowledge of refrigeration theory, pipe-fitting and structural layout, mounts compressor and condenser units on platform or floor, using hand tools, following blueprints or engineering specifications, fabricates, assembles and installs duct-work and chassis parts, using portable metalworking tools and welding equipment, and installs evaporator unit in chassis or in air-duct system, using hand tools. This mechanic observes pressure and vacuum gauges and adjusts controls to insure proper operation, tests joints and connections for gas leaks, using gauges or soap-and-water solution, wraps pipes in insulation batting and secures them in place with cement or wire bands, replaces defective breaker controls, thermostats, switches, fuses and electrical wiring to repair installed units, may install, repair and service air conditioners, ranging from fifteen to twenty tons cooling capacity in warehouses and small factory buildings.