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Lochinvar · Knight (previous generation WH/KH)

Lochinvar Knight WHN055

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.

DiscontinuedHistorically in Canada

Key figures

Max input
55 MBH
Max CSA output
AFUE
95 %
Min input
11 MBH
Natural gasPropaneHeating-onlyresidentialcommercial

Input is gas energy consumed; output is heat delivered. Never size from input alone.

Lochinvar Knight WHN055 in practice

The WHN055 is the 55 MBH wall-hung (WHN) size of the previous-generation Knight fire-tube boiler. Its archived I&O ratings table prints 11-55 MBH input, 51 MBH gross output, a 44 MBH net AHRI water rating, 95% AFUE, 2.5 gallons of boiler water, a 1" water connection, a 1/2" gas connection and a 2" vent size.

Lochinvar keeps the WHN and KHN support pages live under a "Series Discontinued" banner, and the WH 56-400 and KH 55-285 I&O manuals remain publicly hosted so owners can identify the unit and its control. The current Knight fire-tube generations are the WHB wall models and KHB floor models documented separately on Boilers.ca.

Best suited to

  • Owners of an installed WHN055 identifying its ratings and manual
  • Repair-or-replace decisions comparing a legacy Knight with the current WHB/KHB
  • Contractors matching a legacy Knight to its archived I&O before service

Applicability and support

Model number
WHN055
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.

See all service areas

Specifications

Published specifications

Values as published by Lochinvar. Units are shown with every value; notes flag conflicting sources or missing figures.

Lochinvar Knight WHN055 specifications
SpecificationValueNote
Input
Heating input, minimum11 MBHPer the legacy I&O ratings table.
Heating input, maximum55 MBHPer the legacy I&O ratings table.
Output
Gross output51 MBHPer the legacy I&O ratings table.
Net AHRI water rating44 MBHNet AHRI rating based on a piping and pickup allowance of 1.15.
Efficiency
Efficiency (AFUE)95 %AFUE per the legacy I&O ratings table.
Venting and air
Vent size2"Per the legacy I&O ratings table; Canadian installations follow the manual's venting notes.
Physical and connections
Boiler water content2.5 galPer the legacy I&O ratings table.
Water connection1"Per the legacy I&O ratings table.
Gas connection1/2"Per the legacy I&O ratings table.

Frequently asked questions

What are the Knight WHN055 ratings?

The archived I&O ratings table prints 11-55 MBH input, 51 MBH gross output, a 44 MBH net AHRI water rating and 95% AFUE.

Is the WHN/KHN still sold?

No. Lochinvar's support pages carry a "Series Discontinued" banner for these Knight generations; the current fire-tube Knights are the WHB wall and KHB floor lines.

Where can I find the manual?

Lochinvar still hosts the WH 56-400 Installation & Operation Manual (Rev Y) and the KH 55-285 Installation & Operation Manual (Rev J) from the WHN and KHN support pages.

Questions about the Lochinvar Knight WHN055?

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

Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.

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