May operate high or low voltage electrical distribution systems, steam, diesel and gas turbine generators, transformers and switch gears, load centers, motor control centers, panel boards, emergency power and lighting distribution systems, motor generator sets, and uninterrupted power supply systems. 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.