Essential Functions: Essential responsibilities and duties may include, but are not limited to, the following: Installs, operates and maintains heating, air conditioning/refrigeration systems and energy systems; conducts regular preventive maintenance inspections of refrigeration units, heating and ventilating units, including boilers, gas and electrically operated air conditioning equipment and makes necessary adjustments or repairs. Repairs or replaces defective parts in units and equipment and their controls, including thermostats, electronic controllers, automatic switches, fan controls, log switches, damper motors, louvers, relays, filters, belts, compressors, heat exchangers, high-limit controls, pressure controls, safety valves and automatic gas valves.