Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The Knight WHB199 and WHB285 are the two largest common wall-hung Knights: the 285 adds 86 MBH of ceiling (285 versus 199) and 81 MBH of DOE capacity at 95% AFUE, but its minimum fire jumps from 19.9 to 28.5 MBH and 4" venting becomes the only way to reach 100 equivalent feet (3" drops to 50).
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Lochinvar Knight WHB199 | Lochinvar Knight WHB285 |
|---|---|---|
| Heating input, minimum | 19.9 MBH | 28.5 MBH |
| Heating input, maximum | 199 MBH | 285 MBH |
| DOE heating capacity | 183 MBH | 264 MBH |
| AHRI net water rating | 159 MBH | 230 MBH |
| Efficiency (AFUE) | 95 % | 95 % |
| Water content | 5.2 gal | 4.9 gal |
| Space-heating water connections | 1-1/4" | 1-1/4" |
| Gas connection | 1/2" | 1/2" |
| vent-max-2 | — | — |
| Max. equivalent vent/air length, 3" | 100 ft | 50 ft |
| Max. equivalent vent/air length, 4" | — | 100 ft |
| Domestic hot water | Heating-only boiler | Heating-only boiler |
Both are wall-hung heating-only Knights at 95% AFUE sharing 1-1/4" water connections, a 1/2" gas connection and the SMART SYSTEM control, with an indirect tank such as the Squire providing domestic hot water.
The 285 exists for loads the 199 cannot carry: maximum input rises to 285 MBH with 264 MBH of DOE heating capacity. Its 28.5 MBH minimum fire is well above the 199's 19.9 MBH, so in any building whose load stays under 200 MBH the 199 tracks demand more closely.
Venting separates the two most clearly: the 199 reaches 100 equivalent feet in 3" pipe, while the 285's 3" allowance drops to 50 feet and only a 4" system reaches 100. A long or convoluted vent route on the 285 therefore means 4" pipe.
Lochinvar
The Knight WHB199 is the 199 MBH wall-hung Knight: 19.9 to 199 MBH input at 95% AFUE, stepping up to 1 1/4" water connections and 3" venting to 100 equivalent feet.
Lochinvar
The Knight WHB285 is the 285 MBH wall-hung Knight: 28.5 to 285 MBH input at 95% AFUE with 264 MBH DOE capacity, 4" venting available to 100 equivalent feet and 1-1/4" connections.
The WHB199: 100 equivalent feet in 3" pipe. The WHB285 allows 50 feet in 3" and 100 feet only in 4", per Table 3D.
Usually. Its 28.5 MBH minimum fire is a large part-load for a typical house, so the 285 should only be chosen when the heat-loss calculation genuinely needs the ceiling.
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 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.