Velocity Boiler Works’ Raptor stainless-steel, gas-fired condensing boiler features a fire-tube design offering efficiency and performance with a 95% AFUE. It is available in five sizes: 85, 110, 155, 205, and 270 mbh. A 155-mbh combi model also is available, featuring a thermostatic mixing valve and brazed-plate heat exchanger. All include a user-friendly touch screen interface, 5:1 turndown ratio and an outdoor reset function to ensure top performance in response to demand and outdoor temperature changes.