The Navien NFB-H condensing fire tube boiler provides high-efficiency hydronic heating with up to 95% AFUE efficiency and a patented stainless steel fire tube heat exchanger. Designed for residential and light commercial applications, it features up to a 15:1 turndown ratio, built-in zone control connections, flexible venting options, and cascade capability up to sixteen boilers. Its compact wall-hung design, advanced controls, and optional Wi-Fi connectivity deliver reliable, energy-efficient heating performance for modern boiler installations.

• Up to 15:1 turndown ratio
• 2" venting up to 65', 3" venting up to 150'
• Advanced controls with Intuitive user interface and Setup Wizard
• Built-in powered connections for 3 zone valves or 3 zone pumps
• Common venting up to 8 units and cascading up to 16 units
• Next-generation fire tube technology for smarter home heatin