Blog Title: High efficiency fire tube boilers

Main Que: What is a firetube boiler?

Answer: Watertube and firetube boilers are essentially the opposite in design. In a watertube boiler, water travels through tubes which are surrounded by the by-products of combustion, or flue gas. In a firetube boiler, the flue gas travels through the tubes, which are surrounded by hot water. Firetube boilers are typically designed with either three or four sets of tubes (three- or four-pass boilers). Every set of tubes that the flue gas travels through is considered a “pass”. Boilers designed for three-passes have the stack at the rear, and boilers designed for four-passes have the stack at the front. A boiler with more passes has a higher heat extraction rate and is more efficient then one with less passes.