The Classic™ steam boiler and hot water boiler represent the evolution of Fulton’s original vertical tubeless boiler design. Fulton’s Classic boiler design is simple, compact, and trouble-free backed by more than 100,000 boilers installed around the world in virtually every type of industry imaginable. Classic boilers feature efficiencies up to 84% with oil and/or gas capabilities and Low Emissions burner (gas only), all packaged and trimmed for your application.