37 Repair, maintenance, servicing, cleaning, adjusting and/or installation of residential and commercial gas equipment, namely, heating units for heating buildings and water, hot water heaters, incinerators, steam generators, steam tables for cooking, dishwashers, and household natural gas and propane appliances, namely, ranges, cooking ovens and/or microwave ovens, barbecue grills, space heaters, fireplaces, pool heaters, clothes dryers, gas lights, air conditioners, and patio heaters