Responsibilities: Installs, operates, services, and repairs light commercial heat pump/air conditioning systems and other HVAC equipment such as refrigerators, fumehoods, window units, exhaust ventilators, coolers, deep freezers, and unit ventilators. Performs service tasks such as adding refrigerant, lubricating, adjusting and replacing compressors and expansion devices, repairing pumps, cleaning out cooling towers and repacking valve glands and pump seals.