Navien — the leader in condensing wall-hung boilers — officially launched its commercial-sized fire tube boiler series, the NFB-C. The NFB-C is available in two sizes: NFB-301C (301 MBH) and NFB-399C (399 MBH).

Each NFB-C boiler uses the same in-house designed and manufactured patented heat exchanger technology that was introduced with the NFB series in 2018. The heat exchanger is form-pressed and robotic laser welded to minimize the number of weak points that could be prone to thermal stress and corrosion. Oval-shaped tubes within the heat exchanger contain internal turbulators designed to improve both the heat transfer rate and the structural integrity of the assembly. A specific water flow is generated by baffles inside the heat exchanger to extract the maximum amount of heat from flue gasses while the non-metallic base provides additional protection against corrosion caused by acidic condensate.

The industry-leading 97.5 percent thermal efficiency NFB-C series includes top and bottom piping connections for installation flexibility and an advanced 7-inch color touch screen display with easy intuitive navigation for setup, troubleshooting and operation. The built-in circuit board allows connections for a boiler pump and three zones pumps using dry contact relays, and also includes a DHW priority zone. The NFB-C series commercial fire tube boilers offer up to a 15:1 turndown ratio and extremely low NOx levels, certified by SCAQMD to meet the most stringent code requirements.

Optional accessories allow each NFB-C boiler to connect to building management systems through Modbus, BACnet or LonWorks protocols. NFB-C boilers are NaviLink wi-fi remote compatible, cascade capable up to 16 units, common venting capable up to four units and are certified for high-altitude installations up to 10,100 feet.

More information on the new NFB-C commercial fire tube boilers is available at www.navieninc.com.