Burner maintenance or repair; Construction, maintenance and renovation of property; Installation and maintenance of photovoltaic installations; Installation and maintenance of photovoltaic/solar thermal hybrid installations; Installation and maintenance of solar energy based power plants; Installation, maintenance and repair of Ethernet and wireless networks; Installation, repair and maintenance of condensing apparatus, steam condensers, radiators for motors and engines, air reheaters, boiler tubes; Installation, repair and maintenance of heating equipment; Machinery maintenance and repair; Maintenance and repair of burners; Maintenance and repair of heating installations; Maintenance of computer hardware systems; Pump repair and maintenance; Pump repair or maintenance; Repair and maintenance of feed or booster pumps; Repair or maintenance of air-conditioning apparatus; Repair or maintenance of boilers; Repair or maintenance of electric motors; Repair or maintenance of gasoline station equipment; Repair or maintenance of industrial furnaces; Repair or maintenance of industrial washing machines; Repair or maintenance of measuring and testing machines and instruments; Repair or maintenance of vessels; Repair or maintenance of water pollution control equipment; repair or maintenance of storage tanks