Specifications - Navien NHB Series Installation & Operation Manual

1.3 Specifications

The following tables list the specifications for the boiler. Additional specifications for water, gas, electricity, and vent connections are provided
in the Installation section.
Space Heating Specifications
Navien Commercial Condensing Boiler
Heating Input (MBH)
Model
Number 1
Min. Max.
NFB-301C 20 301
NFB-399C 26 399
1. Ratings are the same for natural gas models converted to propane use.
Note
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.
Space Heating Ratings
Gross Net AHRI
Output 2 Rating Water
(MBH) (MBH)
293
389
Thermal
3 Efficiency 2
(%)
255 97.5
338 97.5
Other Specifications
Boiler Water
Water
Content
Pressure
(Gallons)
7.6
12-160 psi
9.6
Water
Connection Size
(Supply, Return)
1¼ in NPT
1½ in NPT
About the Boiler 7