Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
Boilers.ca is a brand of ROMA Heating & Cooling · Licensed gas contractor LGA0202903
Comparison
Verdict in brief
The legacy Knight WHN055 and WHN085 are the two smallest wall-hung fire-tube generations: 11-55 versus 17-85 MBH input, 51 versus 79 MBH gross output, both 95% AFUE with 1" water connections and a 1/2" gas connection. The 085 adds 28 MBH of gross output.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Lochinvar Knight WHN055 | Lochinvar Knight WHN085 |
|---|---|---|
| Heating input, minimum | 11 MBH | 17 MBH |
| Heating input, maximum | 55 MBH | 85 MBH |
| Gross output | 51 MBH | 79 MBH |
| Net AHRI water rating | 44 MBH | 69 MBH |
| Efficiency (AFUE) | 95 % | 95 % |
| Boiler water content | 2.5 gal | 2.5 gal |
| Water connection | 1" | 1" |
| Gas connection | 1/2" | 1/2" |
| Vent size | 2" | 2" |
The WH 56-400 I&O ratings table lists the WHN055 at 11-55 MBH input, 51 MBH gross output and a 44 MBH net AHRI rating; the WHN085 lists 17-85 MBH input, 79 MBH gross output and a 69 MBH net AHRI rating, both at 95% AFUE.
Both print 2" vent sizes, 2.5 gallons of boiler water, 1" water connections and a 1/2" gas connection, so the pair differs mainly in capacity.
The WHN generation is discontinued; owners should confirm the model from the rating plate and use the archived Rev Y I&O manual before service.
Lochinvar
The Lochinvar Knight WHN055 is a discontinued wall-hung fire-tube boiler rated 11-55 MBH input with 51 MBH gross output and a 44 MBH net AHRI water rating at 95% AFUE.
Lochinvar
The Lochinvar Knight WHN085 is a discontinued wall-hung fire-tube boiler rated 17-85 MBH input with 79 MBH gross output and a 69 MBH net AHRI water rating at 95% AFUE.
Capacity: the WHN055 fires 11-55 MBH with 51 MBH gross output and the WHN085 fires 17-85 MBH with 79 MBH gross output, both at 95% AFUE.
No. The WHN is the previous wall-hung Knight generation; Lochinvar keeps its support page under a "Series Discontinued" banner, and the current wall models are the WHB line.
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.