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NFB-C Series

Commercial fire tube boilers


Navien’s high efficiency fire tube condensing technology make NFB-C hard to beat and the easy choice for today’s commercial boiler applications




Navien does it all from start to finish...making NFB-C the total package

  • Robotic and automated manufacturing technology for unmatched quality control.
  • In-house designed and built components, for system matched compatibility...unlike most competitors who use the same out-sourced parts to build their boilers.
  • Lower installation costs with our innovative engineered compact wall hung design, intuitive controls, top or bottom piping connections and flexible venting options.
  • Lower operating costs with the industry’s leading thermal effciency at TE 97.5%...
    Energy Star approved
  • Cascading and common venting capable.
  • Best-in-class training and technical support.
  • One of the industry’s best warranties.
  • Top and bottom piping connections for either floor or wall installations.
  • BMS connectivity (Modbus, BACnet and LonWorks).

  • High altitude installations up to 10,100 ft.

Click here to see what the NFB-C comes with

NFB-C Commercial Fire Tube Boilers

Human innovation meets robotic precision

Patented compact stainless steel fire tube heat exchanger

Navien’s ASME-certified, “H” stamped stainless steel fire tube heat exchangers are in-house designed and built by the latest in robotic and automated technology, reducing high stress point weld failures common on other boilers.


Navien’s advanced patented stainless steel heat exchanger design is ASME‑Certified, “H” Stamped, and reduces high stress point weld failures common on other boilers. This compact, in‑house designed and manufactured heat exchanger uses the latest automated laser welding technology to deliver superior product quality.


Compare these advantages to other boilers

  • 10-1-ratio-nfb-2

    15:1 industry leading
    turndown ratio

    The sophisticated gas flow control  system provides a high turndown ratio which reduces energy waste and excessive boiler cycling while also enhancing temperature  control for DHW.

  • Nfb-c-feature-venting-2022

    Multiple venting options

    Low exhaust gas temperatures  allow use of PVC, CPVC, polypropylene (rigid and flexible)  and stainless steel venting reducing  installation time and costs. System can use 3" venting for up to 60', or up to 150' with 4" venting.

  • Nfb-c-feature-space-saving

    Space saving

    The sleek wall - hung design uses much less space than traditional floor standing boilers, making installations a lot easier.

  • Nfb-c-feature-venturi

    Dual Venturi and field gas convertibility

    Dual Venturi system creates better combustion control and turndown ratio. Orifice conversion kit for easy gas convertibility from NG to LP is included with every NFB-C boiler.

  • Nfb-c-feature-air-filter

    Air intake filter

    This heavy duty inlet air filter has easy access for cleaning and filter media replacement

  • Nfb-c-feature-gaspressure

    Low gas pressure operation

    Negative pressure regulating gas valve ensures maximum performance all the way down to 3.5" of water column on natural gas and 8" of water column on propane gas.

Advanced 7" touch
screen controls

Easy intuitive navigation for setup,
troubleshooting and operation.

Built-in USB port

Download boiler data and settings.
Upload software updates and boiler settings.


Built-in hardware to connect a boiler pump and 3 zone pumps

All integrated into the NFB-C circuit board. Also includes a DHW priority zone.

Cascade up to 32 units
and common vent up to 4 units


With Navien cascading technology, when a boiler gets up to 80% of its capacity the next unit will start to help meet the heating system requirements.

This boiler sequencing will continue until the heating load is fully satisfied. The Navien cascading system also balances out the run hours of each boiler for longer life.

NFB-C Models

Max HTG Input: 301,000 BTU/h
Indoor wall-hung
Navien NFB-301C commercial fire tube boiler
View model
Max HTG Input: 399,000 BTU/h
Indoor wall-hung
Navien NFB-399C commercial fire tube boiler
View model
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