Navien · NFC (first generation)
Navien NFC-175
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.
Key figures
- Max input
- 175 MBH
- Max CSA output
- —
- AFUE
- 95 %
- Min input
- 18 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Navien NFC-175 in practice
The NFC-175 is one of the two original fire-tube NFC combis (NFC-175 and NFC-200) that Navien lists under Discontinued Products ahead of the current NFC-H generation. Its official Technical Data Sheet prints 18–175 MBH heating input with 161 MBH heating capacity, a 140 MBH net AHRI water rating and 95.0% AFUE on natural gas or propane.
The combi produces domestic hot water through its stainless steel DHW module: DHW input reaches 199,900 BTU/h on both models, and the series submittal sheet confirms the 175/200 distinction is the space-heating input (175,000 against 199,900 BTU/h) while the DHW side is rated the same. The unit weighs 145 lb (183 lb with water) in a 17.3 W × 17.3 D × 33.5 H in wall-hung cabinet with 1 1/4" NPT heating connections and 3/4" NPT DHW and gas connections, on 12 – 80 psi hydronic pressure.
The NFC's fire-tube heat exchanger — the design the NFC-H generation continues — carries a 10:1 turndown per the data sheet, and the series supports cascade and common-vent arrangements with NPE water heaters. Because this is the first generation, parts and error codes must be read from the NFC-series documents rather than the current NFC-H manual.
Best suited to
- Owners of an existing first-generation NFC fire-tube combi looking up its ratings
- Comparing the original NFC generation with the current NFC-H line
- Sourcing the correct technical data and submittal documents for an older combi
Applicability and support
- Model number
- NFC-175
- Canadian availability
- historical
- Production status
- discontinued
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Not verified
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 | ||
| Heating input, minimum | 18 MBH | Per the NFC Series Technical Data Sheet. |
| Heating input, maximum | 175 MBH | Per the NFC Series Technical Data Sheet. |
| Output | ||
| Heating capacity | 161 MBH | DOE test basis, per the NFC Series Technical Data Sheet. |
| Net AHRI water rating | 140 MBH | Net AHRI water rating based on a piping and pickup allowance of 1.15. |
| Efficiency | ||
| Efficiency (AFUE) | 95 % | AFUE per the NFC Series Technical Data Sheet. |
| Domestic hot water | ||
| DHW input, minimum | 18 MBH | 18,000 BTU/h. |
| DHW input, maximum | 199.9 MBH | 199,900 BTU/h. |
| DHW connections | 3/4" NPT | DHW inlet and outlet, 3/4" NPT. |
| Venting and air | ||
| Venting | 2" or 3" PVC, CPVC, polypropylene; 2" or 3" special gas vent Type BH (Class III A/B/C) | Forced-draft direct vent per the official specifications. |
| Physical and connections | ||
| Weight | 145 lb | As printed in the official document. |
| Width | 17.3 in | |
| Height | 33.5 in | |
| Depth | 17.3 in | |
| Heating connections | 1 1/4" NPT | Supply and return. |
| Gas connection | 3/4" NPT | |
| Operating limits and other | ||
| Fuel | Natural gas or propane | Ratings are the same for natural gas models converted to propane use; field conversion is licensed gas work. |
| Hydronic water pressure | 12 – 80 psi | DHW side rated 15–150 psi. |
Alerts documented for this model
None documented yet.
Frequently asked questions
What are the ratings of the Navien NFC-175?
The NFC Technical Data Sheet prints 18–175 MBH heating input, 161 MBH heating capacity, a 140 MBH net AHRI water rating and 95.0% AFUE, with DHW input up to 199,900 BTU/h on both NFC models.
Is the Navien NFC-175 still sold?
No. The NFC series (NFC-175, NFC-200) is listed as discontinued; the current fire-tube combi line is the NFC-H series (NFC-250/175H and NFC-250/200H).
What is different between NFC-175 and NFC-200?
Only the space-heating ceiling: 175,000 versus 199,900 BTU/h. Both models share the same 199,900 BTU/h DHW rating, 18 MBH minimum fire, 145 lb cabinet and 95.0% AFUE.
Questions about the Navien NFC-175?
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 — NFC-175 product page (discontinued model downloads) · accessed September 9, 2026
- NFC Series Technical Data Sheet (EN) · accessed September 9, 2026
- NFC Series Submittal Sheet (EN) · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.