Navien · NFB-C Commercial Boiler
Navien NFB-301C
The Navien NFB-301C is the entry model of the wall-hung NFB-C commercial boiler series: 20 to 301 MBH of input with a 293 MBH heating capacity and a 255 MBH net AHRI water rating at 97.5% thermal efficiency, weighing 243 lb empty (307 lb with water).
Key figures
- Max input
- 301 MBH
- Max CSA output
- —
- AFUE
- —
- Min input
- 20 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Navien NFB-301C in practice
The NFB-301C fires from 20,000 to 301,000 BTU/h of input at a printed 97.5% thermal efficiency, with the product page listing a 293,000 BTU/h capacity and a 255,000 BTU/h net AHRI water rating (net figures are based on a piping and pickup allowance of 1.15). It is certified under AHRI certificate no. 201925233, with CRN registrations Z3732.2 (AB), Z3732.21 (BC) and Z3731.24 (MB) printed on the page, and its safety devices are listed as a flame rod, air pressure switch, ignition operation detector, water high-limit switch, exhaust high-limit sensor and water pressure sensor.
At 25.1 x 32.8 x 22.3 in and 243 lb (307 lb with water), the 301C is the lighter of the two NFB-C models, holding 7.6 gallons and connecting on 1 1/4" NPT water and 3/4" NPT gas fittings. It vents in 3" or 4" PVC, CPVC, polypropylene or stainless steel (or special gas vent Type BH, Class III A/B/C) in forced-draft direct-vent or non-direct-vent single-pipe configurations, and Navien's series copy allows 3" runs to 60 ft or 4" to 150 ft. The natural-gas supply range printed for the series is 3.5 to 10.5" wc with an 8 to 13.5" wc propane range.
Best suited to
- Commercial space-heating loads whose heat-loss or plant calculation fits the 20 to 301 MBH input range
- Wall-hung installations with top and bottom piping in a compact 25.1-inch-wide cabinet
- Multi-boiler plants using the NFB-C cascade controls (up to 32 units per the series page)
Applicability and support
- Model number
- NFB-301C
- Canadian availability
- available
- Production status
- current
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Series terms
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Specifications
Published specifications
Values as published by Navien. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input, minimum | 20 MBH | 20,000 BTU/h space-heating input, per the product page. |
| Input, maximum | 301 MBH | 301,000 BTU/h space-heating input, per the product page. |
| Output | ||
| Heating capacity | 293 MBH | 293,000 BTU/h capacity, per the product page. |
| Net AHRI water rating | 255 MBH | 255,000 BTU/h; the net AHRI figure is based on a piping and pickup allowance of 1.15, per the product page. |
| Efficiency | ||
| Thermal efficiency | 97.5 % | As printed on the product page (DOE test basis); the page labels the row "Thermal Efficiency", not AFUE. |
| Venting and air | ||
| Venting | 3" or 4" PVC, CPVC, polypropylene or stainless steel, or 3" or 4" special gas vent Type BH (Class III A/B/C) | Forced-draft direct vent and non-direct vent (single pipe), per the product page. |
| Max. vent length, 3" | 60 ft | 3" venting up to 60 ft, per the NFB-C series page. |
| Max. vent length, 4" | 150 ft | 4" venting up to 150 ft, per the NFB-C series page. |
| Physical and connections | ||
| Weight | 243 lb | 243 lb without water; 307 lb with water, per the product page. |
| Width | 25.1 in | |
| Height | 32.8 in | |
| Depth | 22.3 in | |
| Water content | 7.6 gal | Per the product page. |
| Heating water connections | 1 1/4" NPT | Per the product page. |
| Gas connection | 3/4" NPT | Per the product page. |
| Operating limits and other | ||
| Fuel | Natural gas or propane | The product page states ratings are the same for natural-gas models converted to propane use. |
| Turndown ratio | 15:1 | Per the NFB-C series page; the NFB-399C page prints the same ratio in its input/turndown table. |
| Water pressure rating | 12 – 160 psi | 12–160 PSI water pressure range printed on the NFB-C product pages. |
| Altitude rating | 10,100 ft | Per the NFB-C series page. |
Manuals
- NFB-C Installation and Operation Manual (EN)Ver 1.0 · 2024-02
- NFB-C Service Manual (EN)250116
Alerts documented for this model
Frequently asked questions
What is the input range of the NFB-301C?
20,000 to 301,000 BTU/h, per the product page, with a 293,000 BTU/h heating capacity and a 255,000 BTU/h net AHRI water rating at 97.5% thermal efficiency.
What distinguishes the NFB-301C from the NFB-399C?
Both share the 25.1 x 32.8 x 22.3 in cabinet, venting and 1 1/4" NPT water connections. The 301C fires to 301 MBH and the 399C to 399 MBH, and the 399C is heavier (278 lb against 243 lb) with more water content (9.6 versus 7.6 gallons) and a higher 26 MBH minimum input.
Can the NFB-301C run on propane?
Yes. Navien lists the NFB-C series for natural gas or propane and states ratings are the same for natural-gas models converted to propane use; conversion is licensed gas-fitting work.
Questions about the Navien NFB-301C?
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- Navien Canada — NFB-C series · accessed September 9, 2026
- Navien Canada — NFB-301C product page · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.