Lochinvar · Noble Fire Tube (NKB/NKC/NCF)
Lochinvar Noble NKB080
The Noble NKB080 is the smallest Noble heating boiler: 8.3 to 80 MBH input at 95.0% AFUE with a 1.2-gallon water content, 1" sweat connections and 2" or 3" venting to 100 feet.
Key figures
- Max input
- 80 MBH
- Max CSA output
- —
- AFUE
- 95 %
- Min input
- 8.3 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Lochinvar Noble NKB080 in practice
The NKB080 opens the Noble line as the smallest wall-hung heating-only boiler, firing from 8.3 to 80 MBH of input with 74 MBH of DOE heating capacity and a 64 MBH AHRI net rating at 95.0% AFUE. Its low minimum fire makes it a strong match for well-insulated homes whose heat-loss calculation sits well under 80 MBH.
The boiler uses 1" sweat water connections (combi models use NPT), holds only 1.2 gallons of water and connects gas at 1/2". Venting is Category IV in 2" or 3" pipe, each to 100 equivalent feet at this size, and in Canada the plastic system must be ULC S636 certified. Domestic hot water comes from an indirect tank, and the product page prints a 10-year heat exchanger and 5-year parts warranty.
Best suited to
- Smaller homes whose heat-loss calculation fits under 80 MBH
- Systems pairing a heating-only boiler with an indirect tank
- Projects wanting 95.0% AFUE with the lightest Noble boiler (123 lb shipping weight)
Applicability and support
- Model number
- NKB080L
- 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 Lochinvar. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Heating input, minimum | 8.3 MBH | Per the I&O ratings table. |
| Heating input, maximum | 80 MBH | Per the I&O ratings table. |
| Output | ||
| DOE heating capacity | 74 MBH | DOE heating capacity per the I&O ratings table. |
| AHRI net water rating | 64 MBH | Net AHRI rating based on a piping and pickup allowance of 1.15. |
| Efficiency | ||
| Efficiency (AFUE) | 95 % | 95.0% AFUE per the I&O ratings table. |
| Domestic hot water | ||
| Domestic hot water | Heating-only boiler | The NKB is heating-only; Lochinvar's residential page pairs the Noble wall-mount boiler with the Squire indirect water heater. |
| Venting and air | ||
| Venting | Category IV sealed combustion; PVC, CPVC, polypropylene or stainless steel | In Canada, plastic venting must be a ULC S636-certified system. |
| Max. equivalent vent/air length, 2" | 100 ft | Table 3D (air intake/vent piping sizes), I&O manual. |
| Max. equivalent vent/air length, 3" | 100 ft | Table 3D (air intake/vent piping sizes), I&O manual. |
| Physical and connections | ||
| Water content | 1.2 gal | Per the I&O ratings table. |
| Space-heating water connections | 1" (sweat) | Noble ratings: NPT connections are used on combi units, sweat connections on the boiler. |
| Gas connection | 1/2" | Per the I&O ratings table. |
| Shipping weight | 123 lb | Shipping weight per the Lochinvar product page. |
| Height | 32.876 in | Wall-mounted cabinet, per the Lochinvar product page. |
| Width | 17.063 in | Wall-mounted cabinet, per the Lochinvar product page. |
Manuals
Alerts documented for this model
- Memory Error
- Fan Speed
- LWCO
- Flame Sequence
- Outlet ARHL
- Air Pressure Switch
- AUX Limit Fault
- Flame Fail: Running
- Flame Fail: Ignition
- Flue Temp Limit
- Flue Temp High
- Outlet MRHL
- Outlet Temp High
- Outlet Temp DIFF
- Flue Sensor Fault
- Outlet Sensor Fault
- Inlet Sensor Fault
- Set Point Met
- Anti-Cycling
- Delta T High
- Low Voltage
- No Flue Temp Change
- Combi Sensor Fault (Combi Only)
- Lockout Inlet Sensor Fault
- Outdoor Sensor Missing
- No Hot Water at Faucets (Combi Only)
- DHW Water is not Hot Enough (Combi Only)
- Combi Boiler is Running but Does Not Supply Heated Water to Space Heating System (Combi Only)
- Space Heating System Heat Emitters Get Hot During a DHW Draw and the Combi Boiler does not Provide Hot Enough Domestic Hot Water (Combi Only)
- Lockout! Water Press Switch
Frequently asked questions
Is the NKB080 a combi boiler?
No. The NKB is the heating-only Noble: it has no DHW connections, and the I&O ratings list NPT water connections only for the NKC/NCF combis while the boiler uses 1" sweat connections.
How far can the NKB080 be vented?
In 2" or 3" pipe, each to a maximum of 100 equivalent feet at the 80-110 sizes, per Table 3A of the Noble I&O manual.
Questions about the Lochinvar Noble NKB080?
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.
Compare and explore
- Lochinvar Noble NKB080 vs NKB110Comparison
- Lochinvar Noble NKB110Same series
- Lochinvar Noble NKB150Same series
- Lochinvar Noble NKB199Same series
- Lochinvar Noble NKC110Same series
- Lochinvar Noble NKC150Same series
- Lochinvar Noble NKC199Same series
- Lochinvar Noble NCF110Same series
- Lochinvar Noble NCF150Same series
- Lochinvar Noble NCF199Same series
- Noble Fire Tube (NKB/NKC/NCF) series hub
- Buying guide
Sources and verification
- Lochinvar — Noble Fire Tube Boiler (NKB080L) model page · accessed September 7, 2026
- Noble Fire Tube Boiler and Combi I&O/Service Manual, Rev AN · Rev AN · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.