Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The Royal CO-200 is the top of the Royal CO combi line: DHW input rises from 150 to 200 MBH with flow up from 3.7 to 5.1 GPM at a 70 °F rise (the 'up to 5.1 gpm' figure on the product page), central-heating input from 120 to 180 MBH and heating capacity from 110 to 167 MBH — all at the same 95.2% AFUE in the shared wall-hung cabinet.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Dunkirk Royal CO-150 | Dunkirk Royal CO-200 |
|---|---|---|
| Central-heating input, minimum | 15 MBH | 20 MBH |
| Central-heating input, maximum | 120 MBH | 180 MBH |
| DHW input, minimum | 15 MBH | 20 MBH |
| DHW input, maximum | 150 MBH | 200 MBH |
| DHW flow rate at 70 °F rise | 3.7 gpm | 5.1 gpm |
| AFUE | 95.2 % | 95.2 % |
| Heating capacity | 110 MBH | 167 MBH |
| Net AHRI water rating | 96 MBH | 145 MBH |
| Turndown | Up to 10:1 | Up to 10:1 |
| Dimensions (H x W x D) | 28.23" x 17.4" x 16.93" | 28.23" x 17.4" x 16.93" |
Both combis run the Royal CO platform at 95.2% AFUE with up to 10:1 turndown and the same cabinet and connection sizes. The CO-200's CH side fires 20-180 MBH against the CO-150's 15-120 MBH, lifting heating capacity from 110 to 167 MBH and the net AHRI water rating from 96 to 145 MBH.
On domestic hot water the CO-200 prints DHW input of 200 MBH and 5.1 GPM at a 70 °F rise, against 150 MBH and 3.7 GPM on the CO-150 — the figure behind Dunkirk's '3 Combi Models Offer Domestic Hot Water up to 5.1 gpm' feature bullet. The DHW connections stay 1/2" NPT and the CH side 3/4" NPT on both.
The CO-200's minimum fires step up to 20 MBH (CH) against the CO-150's 15 MBH, so in a low-load home the smaller combi modulates on a lower floor. As with the rest of the line, the gas supply must be sized for the combi's full DHW input during a hot-water draw.
Dunkirk Boilers
The Royal CO-150 is Dunkirk's 150 MBH-class wall-hung residential combi: 15 to 120 MBH central-heating input with DHW input from 15 to 150 MBH (3.7 GPM at a 70 °F rise), 95.2% AFUE, 110 MBH heating capacity and up to 10:1 turndown.
Dunkirk Boilers
The Royal CO-200 is Dunkirk's 200 MBH-class wall-hung residential combi: 20 to 180 MBH central-heating input with DHW input from 20 to 200 MBH (5.1 GPM at a 70 °F rise), 95.2% AFUE, 167 MBH heating capacity and up to 10:1 turndown.
No — it is the combi's DHW flow at a 70 °F temperature rise as printed in the brochure table and summarized as 'up to 5.1 gpm' on the product page.
The CO-200 can draw 200 MBH during a DHW call, so the gas supply must be sized for that input; a licensed contractor confirms the sizing at assessment.
When the heat-loss calculation and simultaneous hot-water draws genuinely exceed the CO-150's 110 MBH heating capacity and 3.7 GPM — extra size without the load just raises the minimum fire.
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.