Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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A. O. Smith · Series
The Conservationist Burkay is A. O. Smith's commercial gas hot-water boiler: a copper heat-exchanger power-burner boiler for indoor high-input applications with inputs up to 670,000 Btu, model family HW-300 through HW-670 — the boiler-line member of the Burkay family (Burkay Genesis is a water-heater sub-brand).
Series facts
A. O. Smith's commercial page presents the Conservationist Burkay as a commercial gas hot-water boiler 'designed for indoor use in installations requiring higher inputs (up to 670,000 Btu)'. The heat exchanger contacts water only through copper, brass and bronze — the page calls the design 'rust-proof' — with a patented combustion design, the Burkay burner, and power-burner gas firing.
The wiring-diagram documents on the page name the model family as HW-300 through HW-670 ('Wiring Diagram For Single Boiler Linear-Temp Installation', 'Four Boiler Linear-Temp Installation HW-300 THRU 670'), so the line spans roughly 300,000 to 670,000 Btu. Efficiency figures live in the spec sheet (AOSDG25600) rather than the captured page text, so no structured percentage is printed here.
Burkay is the classic commercial hot-water supply boiler rather than a space-heating hydronic line. A. O. Smith sells the Burkay Genesis as a separate circulating water-heater sub-brand, which is not part of this boiler hub; the residential combi-boiler category belongs to A. O. Smith's residential site.
Highlights
Models
One canonical page per model with input, output and efficiency kept separate.
A. O. Smith
The A. O. Smith Burkay HW-300 is a commercial gas-fired copper hot water boiler rated 300,000 BTU/h input, with 1-1/4" NPT water connections and a 3/4" NPT gas connection.
A. O. Smith
The A. O. Smith Burkay HW-399 is a commercial gas-fired copper hot water boiler rated 399,000 BTU/h input and 319,200 BTU/h output, with 1-1/2" NPT water connections and a 3/4" NPT gas connection.
A. O. Smith
The A. O. Smith Burkay HW-420 is a commercial gas-fired copper hot water boiler rated 420,000 BTU/h input and 336,000 BTU/h output, with 1-1/2" NPT water connections and a 1" NPT gas connection.
A. O. Smith
The A. O. Smith Burkay HW-520 is a commercial gas-fired copper hot water boiler rated 520,000 BTU/h input and 416,000 BTU/h output, with 2" NPT water connections and a 1" NPT gas connection.
A. O. Smith
The A. O. Smith Burkay HW-670 is a commercial gas-fired copper hot water boiler rated 660,000 BTU/h input (670,000 BTU/h on propane) and 536,000 BTU/h output, with 2" NPT water connections and a 1" NPT gas connection.
| Specification | A. O. Smith Burkay HW-300 | A. O. Smith Burkay HW-399 | A. O. Smith Burkay HW-420 | A. O. Smith Burkay HW-520 | A. O. Smith Burkay HW-670 |
|---|---|---|---|---|---|
| input-min | — | — | — | — | — |
| Input rating | 300,000 BTU/h natural and propane | 399,000 BTU/h natural and propane | 420,000 BTU/h natural and propane | 520,000 BTU/h natural and propane | 660,000 BTU/h natural / 670,000 BTU/h propane |
| Output rating | Not present in the AOSDG25600 PDF text layer | 319,200 BTU/h | 336,000 BTU/h | 416,000 BTU/h | 536,000 BTU/h |
| afue | — | — | — | — | — |
| turndown | — | — | — | — | — |
| vent-max-3 | — | — | — | — | — |
| vent-max-2 | — | — | — | — | — |
| Approximate shipping weight | 250 lb | 301 lb | 301 lb | 381 lb | 381 lb |
Read the full comparison: A. O. Smith Burkay HW-300 vs HW-420 →
Read the full comparison: A. O. Smith Burkay HW-420 vs HW-670 →
Read the full comparison: A. O. Smith Burkay HW-300 vs HW-399 →
Read the full comparison: A. O. Smith Burkay HW-399 vs HW-420 →
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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.
Services for A. O. Smith boilers
The Conservationist Burkay is sold as a commercial gas hot-water boiler (copper heat exchanger, power-burner, up to 670,000 Btu). The Burkay Genesis sub-brand, by contrast, is a circulating water heater, not a boiler.
A. O. Smith positions it for indoor high-input commercial hot-water supply installations rather than hydronic space heating.
The official wiring-diagram documents name the family as HW-300 through HW-670, and the page headline is 'inputs up to 670,000 Btu'. Per-model steps are in the spec sheet.
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.