As the HVAC Master Mechanic, you will install, service and repair environmental-control systems in residences, department stores, office buildings, and other commercial establishments, utilizing knowledge of refrigeration theory, pipefitting and structural layout, mounts compressor and condenser units on platform or floor, using hand tools, following blueprints or engineering specifications, fabricates, assembles and installs ductwork and chassis parts, using portable metalworking tools and welding equipment, and installs evaporator unit in chassis or in air-duct system, using hand tools. 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 one hundred and fifty tons cooling capacity in warehouses and other large buildings.