The Precision Boilers FTH Flexible Watertube Hot Water Boiler’s flextube forced draft design offers high fuel-to-output efficiency in a compact, maintenance-friendly design. It harnesses natural heat convection to ensure consistent internal heat distribution and complete internal water circulation. Noted for its small footprint compared to a horizontal firetube, the FTH Flexible Watertube Hot Water Boiler fuel-fired hot water boiler accommodates up to 150°F temperature differences from the supply and return.

Features & Benefits

• Virtually instantaneous hot water
• Individual carbon steel tubes bent into a serpentine configuration connect the lower return water vessel to the upper supply water vessel to form a five-pass heat transfer space that provides approx. 5 sq. ft. of heating surface per BHP
• A single down-comer connects the upper and lower vessels outside the boiler cabinet to optimize natural internal convection and ensure positive water circulation through the heating tubes, resulting in a pressure vessel that accommodates up to 150oF temperature rise between supply and return to deliver hot water almost instantaneously without the risk of thermal shock
• FTH-1/2/3 Series hot water boilers are configured with tangent water walls on three sides of the combustion chamber requiring tube removal clearance on only one side of the boiler
• FTH-4/5/6 Series hot water boilers are configured with tangent water walls on four sides of the combustion chamber requiring tube removal clearance on both sides of the boiler
• All models can be supplied in a ‘knock-down’ condition to fit where access is limited, then reassembled with NO on-site code welding required
• Available in low NOx configurations as low as sub-9ppm
• 25-year warranty protecting the vessel against thermal shock