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- 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
NFB-399C premium features and benefits
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.
Patented stainless steel fire tube heat exchangerNavien’s innovative heat exchanger design is ASME‑Certified,“H” Stamped, and reduces high-stress point weld failures common on other combi-boilers.
Dual Venturi and field gas convertibility. Dual Venturi system creates better combustion control and turndown ratio. Orifice for easy field gas convertibility from NG to LP. Conversion kits included.
Top and bottom piping
Easy pipe connections for floor or wall-hung installations.
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.
Built-in hardware connects boiler pump & 3 zone pumps. All integrated into the NFB-C circuit board. Also includes a DHW priority zone
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.
|Water volume||36.3 l (9.6 gal)|
|Dimensions||63.8cm W x 83.3cm H x 56.6cm D (25.1″ W x 32.8″ H x 22.3″ D)|
|Boiler weight||126.1 kg (278 lbs)|
|Boiler Weight With Water||168.3 kg (371 lbs)|
|Installation type||Indoor wall-hung|
|Venting type||Forced draft direct vent and non-direct vent (single pipe)`|
|Natural gas supply pressure (from source)||3.5 ” WC to 10.5 ” WC|
|Propane gas supply pressure (from source)||8 ” WC to 13.5 ” WC|
|Natural gas manifold pressure (min-max)||-0.03 ” WC to -1.9 ” WC|
|Propane gas manifold pressure (min-max)||-0.01 ” WC to -0.9 ” WC|
|Connection sizes||Gas inlet||3/4″ NPT|
|Power supply||Main supply||120V AC, 60Hz|
|Maximum power consumption||Less than 12 amperes|
|Materials||Casing||Cold rolled carbon steel|
|Heat exchangers||Stainless steel|
|Venting||Exhaust||3″ or 4″ PVC, CPVC, PP and SS / 3″ or 4″ special gas vent type BH (Class III, A/B/C|
|Intake||3″ or 4″ PVC, CPVC, PP and SS / 3″ or 4″ special gas vent type BH, (Class III, A/B/C)|
|Vent clearances||0″ to combustibles|
|Safety Devices||Flame rod, APS, Ignition operation detector, Water temperature high limit switch, Exhaust temperature high limit sensor, Water pressure sensor|