Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The NCB-210E and NCB-240E are the larger NCB-E combis: both 95.0% AFUE, both 84 lb and both starting at 18 MBH, but the 240E raises the heating ceiling from 100 to 120 MBH, capacity from 94 to 112 MBH and DHW input from 180,000 to 199,900 BTU/h, with flow of 4.5 GPM against 4.0 GPM at a 77°F rise.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Navien NCB-210E | Navien NCB-240E |
|---|---|---|
| Heating input, minimum | 18 MBH | 18 MBH |
| Heating input, maximum | 100 MBH | 120 MBH |
| Heating capacity | 94 MBH | 112 MBH |
| Net AHRI water rating | 82 MBH | 97 MBH |
| Efficiency (AFUE) | 95 % | 95 % |
| DHW input, maximum | 180 MBH | 199.9 MBH |
| DHW flow rate at 77°F (43°C) rise | 4 GPM | 4.5 GPM |
| Weight | 84 lb | 84 lb |
The NCB-210E and NCB-240E sit at the top of the NCB-E line. The specification sheet prints identical 18 MBH minimum fires, so both modulate down the same amount in mild weather; the difference is at the top — 100 against 120 MBH of heating input, 94 against 112 MBH of capacity and an 82 against 97 MBH net AHRI water rating, all at 95.0% AFUE.
Domestic hot water follows the same pattern: 180,000 against 199,900 BTU/h of DHW input and 4.0 against 4.5 GPM at a 77°F (43°C) rise. That 240E ceiling is the highest in the NCB-E generation and matches the original NCB-240's DHW rating, while the heating side stays below it — a reminder that on a combi the two sides are sized independently.
Both units weigh 84 lb in the shared 17 x 28 x 12 in cabinet with 1" NPT heating connections, 3/4" NPT DHW and gas connections and 2"/3" venting. Since the generation is discontinued, a replacement decision should weigh the current NCB-H models, whose 240-class combis add the H-series control and code set.
Navien
The Navien NCB-210E is a previous-generation wall-hung condensing combi from the discontinued NCB-E series: 18 to 100 MBH heating input, 94 MBH capacity at 95.0% AFUE, and DHW input to 180,000 BTU/h.
Navien
The Navien NCB-240E is a previous-generation wall-hung condensing combi from the discontinued NCB-E series: 18 to 120 MBH heating input, 112 MBH capacity at 95.0% AFUE, and DHW input to 199,900 BTU/h.
The 240E adds 20 MBH of heating ceiling (120 against 100), 19,900 BTU/h of DHW input (199,900 against 180,000) and 0.5 GPM of flow at a 77°F rise. Minimum fire, weight, cabinet and AFUE are identical.
Both print a 199,900 BTU/h DHW input ceiling and 4.5 GPM at a 77°F rise, so the documented hot-water capability matches, though the two generations use different controls and error-code sets.
That is a decision for a licensed contractor after diagnosing the fault. Parts remain available and the official NCB-E service manual is still published; if replacement is chosen, the current NCB-H line is the successor generation.
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.