Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The two first-generation NFC fire-tube combis differ only in the space-heating ceiling: the NFC-175 fires to 175 MBH with 161 MBH capacity, the NFC-200 to 199 MBH with 183 MBH capacity. Both share the same 199,900 BTU/h DHW rating, 18 MBH minimum fire, 145 lb cabinet and 95.0% AFUE.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Navien NFC-175 | Navien NFC-200 |
|---|---|---|
| Heating input, minimum | 18 MBH | 18 MBH |
| Heating input, maximum | 175 MBH | 199 MBH |
| Heating capacity | 161 MBH | 183 MBH |
| Net AHRI water rating | 140 MBH | 159 MBH |
| Efficiency (AFUE) | 95 % | 95 % |
| DHW input, maximum | 199.9 MBH | 199.9 MBH |
| Weight | 145 lb | 145 lb |
The NFC-175 and NFC-200 are the original fire-tube NFC combis. The Technical Data Sheet prints an 18 MBH minimum fire for both, a 161 MBH capacity for the 175 against 183 MBH for the 200, and net AHRI water ratings of 140 and 159 MBH — all at 95.0% AFUE on natural gas or propane.
Unlike the heating side, the domestic hot water rating is identical: both models print a maximum DHW input of 199,900 BTU/h, so the choice between them is entirely about how much space heating the building needs. Both share the 145 lb (183 lb with water) wall-hung fire-tube cabinet at 17.3 W x 17.3 D x 33.5 H in, with 1 1/4" NPT heating connections and 3/4" NPT DHW and gas connections.
The fire-tube exchanger carried a 10:1 turndown per the data sheet and 12–80 psi hydronic pressure on both models. As first-generation products, they are listed as discontinued, and their parts and error codes should be read from the NFC-series documents rather than the current NFC-H manual.
Navien
The Navien NFC-175 is a first-generation fire-tube condensing combi from the discontinued NFC series: 18 to 175 MBH heating input with 161 MBH capacity at 95.0% AFUE and DHW input to 199,900 BTU/h.
Navien
The Navien NFC-200 is a first-generation fire-tube condensing combi from the discontinued NFC series: 18 to 199 MBH heating input with 183 MBH capacity at 95.0% AFUE and DHW input to 199,900 BTU/h.
Yes. Both print a maximum DHW input of 199,900 BTU/h; only the space-heating ceiling differs — 175,000 against 199,900 BTU/h.
The NFC-200, when the room-by-room heat-loss calculation exceeds the NFC-175's 175 MBH ceiling. Both are otherwise the same 145 lb combi with identical DHW ratings.
No. The NFC series (NFC-175, NFC-200) is discontinued; the current fire-tube combi line is the NFC-H series, with different model names and its own manuals.
A consultation includes a heat-loss review so the size is right the first time.
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.