AN UPDATE ABOUT COVID-19:Health and safety is at the heart of everything we do.Learn more
NFB-399C certifications
high efficiency Condensing Heating Boiler
  • 97.5% TE Industry Leading Thermal Efficiency
  • Patented stainless steel fire tube heat exchanger
  • 160 PSI maximum operating pressure
  • Advanced controls with intuitive 7” color display
  • Up to 15:1 TDR (turndown ratio)
  • BAS communication capability
  • Common vent up to 4 and cascade up to 32 units
  • Top & bottom piping
Credits & Rebates Finder
Find Sales Rep

NFB‑C: the inside story

NFB‑C: the inside story
Navien Rebate Finder
Installer/Service Locator
Distributor/Sales Rep
Product Registration

Use our NPE sizing calculator

Download the Navisizer app

Navien Installer/Services Locator

Find the nearest Navien Service Specialist including installers and service providers.

Distributor & sales rep locator

Enter your state, city, or zip code to find a Navien Sales rep or distributor near you.

Product Registration

Online Product Registration

Navien uses the information from our web site to measure statistics such as: number of visits, pages visited, and information requested. 
Navien will never send unsolicited e-mail or share the e-mail or url address with other companies.

Customer Information

See Privacy Policy about collection and usage of your Personal Information.

Product Serial number is 15-16 digits and can be found either on the right side of the box or the back of the front cover.
Navien, Inc. Technical Customer Service Department

Training Information

Navien Academy
Go to Calendar

Navien Virtual Trainings
See Classes

Academy Experience
Watch video

In-Field Training
Find training near you