860 MBH to 17,220 MBH (25 BHP to 500 BHP) up to 86% efficiency
Flex-tube forced draft design offers high fuel-to-output efficiency in a compact, maintenance-friendly design that harnesses natural heat convection to ensure consistent internal heat distribution and complete internal water circulation. Noted for their small footprint compared to a horizontal fire-tube, the FTH accommodates up to 150oF temperature differences from the supply and return, and offers virtually instantaneous hot water. The FTH can be configured to communicate with any building management system. Other available options include construction under ASME Section I/VIII for high temperature hot water applications.