Navien · NCB (first generation)
Navien NCB-180
The Navien NCB-180 is a first-generation wall-hung condensing combi from the discontinued NCB series: 14 to 80 MBH of heating input with 74 MBH heating capacity, 93.5% AFUE and DHW input to 150,000 BTU/h.
Key figures
- Max input
- 80 MBH
- Max CSA output
- —
- AFUE
- 93.5 %
- Min input
- 14 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Navien NCB-180 in practice
The NCB-180 is one of the three original NCB combi models Navien lists under Discontinued Products on both navieninc.ca and navieninc.com. Per the NCB Installation and Operation Manual, it fires 14 to 80 MBH for space heating with a 74 MBH heating capacity and a 64 MBH net AHRI water rating, at 93.5% AFUE.
On the domestic hot water side the NCB-180 fires 14,000 to 150,000 BTU/h and delivers 3.4 GPM at a 77°F (43°C) temperature rise, with a 0.5 GPM minimum flow. It is a true combi — DHW is produced inside the unit through its stainless steel domestic-water heat exchanger — in a 74 lb cabinet measuring 17 × 28 × 12 in with 1" NPT heating connections and 3/4" NPT DHW and gas connections.
Venting is 2" or 3" PVC, CPVC or polypropylene (or special gas vent Type BH), hydronic pressure is rated 12 – 30 psi and the DHW side 15–150 psi. The NCB installation manual states installation up to 10,100 ft for natural gas and 4,500 ft for propane. Owners should match parts and error codes to the NCB generation's own service manual, because Navien's later NCB-E and NCB-H tables changed code meanings between generations.
Best suited to
- Owners of an existing first-generation NCB looking up its printed ratings and manuals
- Understanding the input, capacity and DHW range of Navien's original combi line
- Matching a replacement decision to the documented NCB generation, not a later model
Applicability and support
- Model number
- NCB-180
- 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 | 14 MBH | Per the NCB Installation and Operation Manual. |
| Heating input, maximum | 80 MBH | Per the NCB Installation and Operation Manual. |
| Output | ||
| Heating capacity | 74 MBH | DOE test basis, per the NCB Installation and Operation Manual. |
| Net AHRI water rating | 64 MBH | Net AHRI water rating based on a piping and pickup allowance of 1.15. |
| Efficiency | ||
| Efficiency (AFUE) | 93.5 % | AFUE per the NCB Installation and Operation Manual. |
| Domestic hot water | ||
| DHW input, minimum | 14 MBH | 14,000 BTU/h. |
| DHW input, maximum | 150 MBH | 150,000 BTU/h. |
| DHW flow rate at 77°F (43°C) rise | 3.4 GPM | Per the NCB Installation and Operation Manual; minimum DHW flow 0.5 GPM. |
| 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 | 74 lb | As printed in the official document. |
| Width | 17 in | |
| Height | 28 in | |
| Depth | 12 in | |
| Heating connections | 1" 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 – 30 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 NCB-180?
The NCB manual prints 14–80 MBH heating input, 74 MBH heating capacity, a 64 MBH net AHRI water rating and 93.5% AFUE, with DHW input of 14,000–150,000 BTU/h and 3.4 GPM at a 77°F rise.
Is the Navien NCB-180 still sold?
No. Navien lists the original NCB series (NCB-180, NCB-210, NCB-240) under Discontinued Products on both navieninc.ca and navieninc.com; the current Canadian combis are the NCB-H and NFC-H series.
Where can I get the NCB-180 manual?
Navien still hosts the NCB Installation and Operation Manual and NCB Service Manual on navieninc.com, linked from the official NCB-180 product page; the manual is the reference for this model's ratings and error codes.
Questions about the Navien NCB-180?
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 — NCB-180 product page (discontinued model downloads) · accessed September 9, 2026
- NCB Installation and Operation Manual (EN) · accessed September 9, 2026
- Navien Canada — discontinued products · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.