Graduate of heating, HVAC, ventilation, air conditioning, and refrigeration apprenticeship program from the U.S. Air Force; Or 2. Must have been an enlisted machinery technician (MK) with the U.S. Coast Guard OR possession of a certificate as a Marine Engineer issued by the U.S. Coast Guard; Or 3. Must have been an enlisted power generation equipment repairer with the U.S. Army; Or 4. Must have been an enlisted gas turbine systems technician, submarine nuclear propulsion plant operator reactor control, utilities man, machinist mate, or engineman with the U.S. Navy; Or 5. Duties Description Operates, maintains, and repairs steam and hot water boilers, water supply and return systems, electronic and pneumatic combustion and heating, ventilation and air conditioning (HVAC) control systems, forced or induced draft fan systems, chiller systems, and other refrigeration equipment.