Unilux hot water boilers offer 85% efficiency with a five-pass gas side flow pattern steel bent watertube and forced-draft combustion technology. The boilers offer thermal shock resistance, high operating efficiencies, improved heat transfer characteristics, increased gas side velocities, high natural internal circulation rates, low water volume and rapid heat-up time. Capacities from 20 to 2,000 bhp are offered, with low NOx emissions.Unilux Boiler Corp.