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NFB700-500C premium features and benefits
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 controls.
All system setup, operations and troubleshooting available at your fingertips with the 10.1" color display panel, intuitive text information makes everything easier.
Built-in hardware connections for a boiler pump and 4 zone pumps.
All integrated into the NFB700-C circuit board, including DHW priority zone and air handler.
Dual Venturi system.
Maintains precise combustion and stable turndown ratios.
Patented stainless steel fire tube heat exchanger.
ASME-certified, H-stamped, and engineered for durability to reduce stress-related weld failures.
Multiple venting options.
Supports PVC, CPVC, polypropylene, and stainless steel venting (up to 150 ft), reducing install time and cost.
NFB700-500C QuickFacts
23.8" W x 72.1" H x 31.0" D (60.5cm W x 183.1cm H x 78.7cm D)
| Item | Temperature Setting Range | |
|---|---|---|
| Space Heating | Supply | 77 - 190 °F (25 - 87.78 °C) |
| Return | 68 - 158 °F (20 - 70 °C) | |
Actual supply and return temperatures vary depending on the selected outdoor reset curve.
Navien Commercial Condensing Boiler Space Heating Ratings | ||
|---|---|---|
| Model1 | NFB700-500C | |
| Heating Input | Min | 40 MBH |
| Max | 499 MBH | |
| Heating Capacity2 | 487 MBH | |
| Net AHRI Rating, Water3 | 423 MBH | |
| Thermal Efficiency2 | 97.5 | |
Other Specifications | ||
| Boiler Water Content | 26.5 gal (100.31 l) | |
| Water pressure | Min | 12 PSI (0.8 kg/cm2) |
| Max | 160 PSI (11.2 kg/cm2) | |
| Water Connection Size (Supply, Return) | 2 in NPT | |
1 Ratings are the same for natural gas models converted to propane use.
2 Based on U.S. Department of Energy (DOE) test procedures.
3 The net AHRI water ratings shown are based on a piping and pickup allowance of 1.15.
Consult Navien before selecting a boiler for installations having unusual piping and pickup requirements,
such as intermittent system operation, extensive piping system, etc.
| Item | NFB700-500C | |
|---|---|---|
| Dimensions | 23.8" W x 72.1" H x 31.0" D (60.5cm W x 183.1cm H x 78.7cm D) | |
| Boiler weight | 622 lbs (282.1 kg) | |
| Boiler Weight With Water | 843 lbs (382.4 kg) | |
| Installation location | Floor standing | |
| Venting type | Forced draft direct vent | |
| Ignition | Electronic ignition | |
| Natural gas supply pressure (from source) | 3.5 " WC to 10.5 " WC (0.87 kPa to 2.61 kPa) | |
| Propane gas supply pressure (from source) | 8 " WC to 13 " WC (1.99 kPa to 3.23 kPa) | |
| Natural gas manifold pressure (min-max) | -0.01 " WC to -0.3 " WC (-0.0025 kPa to -0.075 kPa) | |
| Propane gas manifold pressure (min-max) | -0.01 " WC to -0.3 " WC (-0.0025 kPa to -0.075 kPa) | |
| Connection sizes | Gas inlet | 1 in NPT |
| Power Supply | Main supply | 120 V AC, 60 Hz |
| Maximum power consumption | Less than 12 amperes | |
| Materials | Casing | Cold-rolled carbon steel |
| Heat exchangers | Stainless Steel | |
| Venting | Exhaust | 4 in PVC, CPVC, approved polypropylene, approved stainless steel 4 in special gas vent Type BH (Class III, A/B/C) |
| Intake | 4 in PVC, CPVC, polypropylene, stainless steel 4 in special gas vent Type BH (Class III, A/B/C) | |
| Safety Devices | Flame rod, APS, ignition operation detector, water temperature high limit sensor, exhaust temperature high limit sensor, LWCO (low water cut off), high gas pressure switch, low gas pressure switch | |
| Certifications | CSA, SCAQMD 1146.2, ASME Certified, Energy star certified | |
Navien reserves the right to change specifications at any time without prior notice.
| NFB700-C Coverage Table for Heat Exchanger and Parts Only | |
| Commercial | |
| Heat Exchanger | 10 Years |
| Parts | 3 Years |
Compare NFB700‑C models
NFB700‑C Videos
NFB700-500C FAQs
What types of commercial buildings is the NFB700-C best suited for?
The NFB700-C is ideal for a wide range of commercial and industrial applications, including schools, multi-family residences, office complexes, hospitals, light manufacturing facilities, and anywhere high-capacity, high-efficiency space heating is required.
Can the NFB700-C be integrated into a building management system (BMS)?
Yes, the NFB700-C is compatible with Navien's building automation system (BAS) interfaces and supports BACnet or LonWorks via optional gateway.
What kind of maintenance access does the floor-standing design provide?
The vertical floor-standing layout allows top, front, and side access to key service components, including the heat exchanger, control panel, and gas/water connections, simplifying maintenance in tight mechanical rooms.
Does the NFB700-C support outdoor reset controls?
Yes, it’s fully compatible with outdoor reset controls, which allow the boiler to automatically adjust supply temperatures based on outdoor conditions, improving energy savings and comfort.
What venting options are available for the NFB700-C?
The NFB700-C supports multiple venting configurations, including direct vent and common venting for up to four units. It accommodates vent lengths up to 150 feet and uses standard 4" or 6" vent connections, providing flexibility for a wide range of commercial installation scenarios.