Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Navien · Series
The NFB-C is Navien's wall-hung commercial fire-tube condensing boiler series for Canada: the NFB-301C and NFB-399C fire from 20 and 26 MBH up to 301 and 399 MBH at a printed 97.5% thermal efficiency, with 15:1 turndown, 3" or 4" venting and cascade control for up to 32 units.
Series facts
97.5% thermal efficiency per the NFB-C series page and the model product pages, which print a "Thermal Efficiency" row (DOE test basis), not AFUE.
Navien positions the NFB-C as a commercial fire-tube condensing boiler that hangs on the wall: the two Canadian models, NFB-301C and NFB-399C, fire from 20,000 and 26,000 BTU/h up to 301,000 and 399,000 BTU/h at 97.5% thermal efficiency, and the series page headlines the efficiency as "industry leading" alongside its Energy Star approval claim. Turndown is printed at 15:1, and the series page claims cascade control of up to 32 units with common venting of up to 4 units.
Venting is 3" or 4" PVC, CPVC, polypropylene or stainless steel (plus special gas vent Type BH, Class III A/B/C), with the series page stating 3" runs to 60 ft and 4" runs to 150 ft. The NFB-C is a heating boiler with no integrated hot-water production: Navien's copy lists a built-in boiler pump, three zone pump drivers and a DHW priority zone for an external hot-water source, along with an inlet air filter, a 7" touch screen with USB, and BMS communication via Modbus, BACnet or LonWorks.
Navien states the series runs down to 3.5" wc natural gas or 8" wc propane supply pressure, includes a Dual Venturi NG-to-LP conversion kit, and is rated to 10,100 ft altitude. The stainless fire-tube heat exchanger is ASME "H"-stamped and built in-house per the series page. The model pages print a "Residential/Commercial" badge, and the Canadian site lists the NFB-C under both Commercial and Residential "Boilers" navigation, while the discontinued-products list does not include it.
Highlights
Navien's published NFB-C warranty, per the product pages: Commercial coverage of 1-year labour / 3-year parts / 10-year heat exchanger, with a residential schedule (1/5/heat-exchanger per the page's warranty table) also listed for single-family installs.
Models
One canonical page per model with input, output and efficiency kept separate.
Navien
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).
Navien
The Navien NFB-399C is the top model of the wall-hung NFB-C commercial boiler series: 26 to 399 MBH of input with a 389 MBH heating capacity and a 338 MBH net AHRI water rating at 97.5% thermal efficiency, in the same cabinet as the NFB-301C at 278 lb.
| Specification | Navien NFB-301C | Navien NFB-399C |
|---|---|---|
| Input, minimum | 20 MBH | 26 MBH |
| Input, maximum | 301 MBH | 399 MBH |
| output-max | — | — |
| afue | — | — |
| Turndown ratio | 15:1 | 15:1 |
| Max. vent length, 3" | 60 ft | 60 ft |
| vent-max-2 | — | — |
| Weight | 243 lb | 278 lb |
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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.
Services for Navien boilers
Navien Canada lists two: the NFB-301C, firing 20,000 to 301,000 BTU/h, and the NFB-399C, firing 26,000 to 399,000 BTU/h, both rated at a printed 97.5% thermal efficiency.
The Canadian site lists the NFB-C under Commercial → Boilers, and the model pages print a "Residential/Commercial" badge. Boilers.ca records the series for commercial applications; a project's actual application is confirmed with the supplier.
The NFB-C series page claims cascade control of up to 32 units with common venting of up to 4 units. Venting per the same page is 3" to 60 ft or 4" to 150 ft.
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On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.