The XFyre™ and XTherm™ are commercial modulating, condensing boilers. The boilers are now CSA-Certified for polypropylene venting, when used with Centrotherm Innoflue venting components. Innoflue polypropylene venting is ULC-S636- and UL-1738-approved. According to the manufacturer, polypropylene is nearly as economically priced as PVC, much lower than CPVC, has a lower installation cost than either (no primers or glues needed) and allows a higher flue temperature rating than PVC. A customized, easily field installed adaptor kit, with new, high-temperature limit, is available.