The XVers vertical fire-tube modulating condensing stainless steel boiler comes in sizes 855 to 3,000 MBTU. The XVers boiler is now available with the HO2T system. HO2T continuously monitors the oxygen level of the flue gas in the vent piping. If the oxygen level deviates from the target set point (operating curve), HO2T will modulate the fuel gas flow via the actuator and valve and bring the oxygen back to the target set point. This built-in, automatic system protection that extends the life of an XVers by maintaining the optimum fuel to air ratio. The XVers provides extreme versatility for boiler applications, with cutting-edge control technology, broad installation flexibility, easy commissioning, optimum seasonal efficiency, and long-term reliability.