All Raypak XFyre and Xtherm boilers are CSA-certified for polypropylene venting and Centrotherm Innoflue R venting. Innoflue polypropylene venting is ULC S636- and UL 1738-approved. Polypropylene is economically priced, has a lower installation cost and allows a higher flue temperature. Raypak offers a customized, field-installed adaptor kit with higher temperature limit. Polypropylene venting assures safe and reliable operation for hydronic systems up to 200° F outlet temperature for virtually all U.S. climates.