The Cleaver-Brooks CB model can be found in boiler rooms around the world. It a 4-pass dryback boiler with integral air atomizing burner. Combustion air is delivered through a rotary air damper located in the front head. Steam boilers up to 700 HP boast five square foot of heat transfer surface area per boiler horsepower, while the 800 HP model utilizes 4.375. The CB model later became the CBLE which includes an integral flue-gas recirculation system for emission reduction. Flue gas is mixed with combustion air inside of the front head, resulting in no external FGR piping. Model CB and CBLE are available from 25 HP to 800 HP in pressures from 15# to 300#, and in a wide variety of gaseous and liquid fuels.