Dryback – Available in steam or hot water versions, 15 – 800 hp, pressures to 300 psig, two-pass and three-pass design. 81% minimum efficiency. Davited rear doors. Low maintenance. 5 sq. ft. heating surface/HP. Durable design. Heavily constructed. Wetback – Available in steam or hot water versions. Three pass and four pass wetback design, 30 to 1800 HP, 15 to 300# steam, 30 to 160# hot water. Three-pass and four pass wetback design eliminates refractory baffles between flue gas passes. Minimum maintenance with rugged construction for extra-long life. UL listed boiler/burner package for firing gas, oil and combination gas/oil. Factory tested and checked for optimum operating efficiency.