- Wholesalers of Heating, Air Conditioning, Supplies, Tools, Pipe-Fittings, Valves, Boilers, Burners, Plumbing Fixtures National Sales specializes in a full and diverse inventory that includes many older and hard-to-find items for the Mechanical Contractor and PVF Industry. We have more than 30000 sku's in stock and over 100, 000 square feet of warehouse space. Just want a sales person St. Louis ...www.nationalsalesco.com