Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The Dunkirk WPSB-6D and Dunkirk WPSB-7D are both non-condensing boilers in the Dunkirk Boilers WPSB Series 4 line. Published ratings: Dunkirk WPSB-6D at 187.5 MBH input, 157 MBH heating capacity and 84.1% AFUE; Dunkirk WPSB-7D at 225 MBH input, 188 MBH heating capacity and 84% AFUE. Dunkirk WPSB-7D lists 37.5 MBH more input than Dunkirk WPSB-6D (225 MBH against 187.5 MBH). Dunkirk WPSB-6D carries the higher published AFUE at 84.1%, against 84%. Dunkirk WPSB-7D lists 67 lb more shipping weight than Dunkirk WPSB-6D (601 lb against 534 lb).
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Dunkirk WPSB-6D | Dunkirk WPSB-7D |
|---|---|---|
| Input | 187.5 MBH | 225 MBH |
| Heating capacity | 157 MBH | 188 MBH |
| Net AHRI water rating | 137 MBH | 163 MBH |
| Efficiency (AFUE) | 84.1 % | 84 % |
| Domestic hot water | Heating-only boiler — domestic hot water comes from a separate indirect tank or water heater | Heating-only boiler — domestic hot water comes from a separate indirect tank or water heater |
| Boiler water content | 11.7 gal | 13.5 gal |
| Shipping weight | 534 lb | 601 lb |
| Dimensions | 21" wide x 36-3/8 in. high x 26-1/2 in. deep | 24-1/4" wide x 36-3/8 in. high x 26-1/2 in. deep |
| Gas connection | 1/2 in. NPT gas inlet; 1-1/4 in. water return/supply (all models). | 1/2 in. NPT gas inlet; 1-1/4 in. water return/supply (all models). |
| Electrical | 120 V AC / 60 Hz / 1 phase, less than 12 A (15 A circuit recommended) | 120 V AC / 60 Hz / 1 phase, less than 12 A (15 A circuit recommended) |
| Fuel | Natural gas or propane | Natural gas or propane |
Published ratings: the Dunkirk WPSB-6D is rated 187.5 MBH input, 157 MBH heating capacity and 84.1% AFUE; the Dunkirk WPSB-7D is rated 225 MBH input, 188 MBH heating capacity and 84% AFUE. Dunkirk WPSB-7D lists 37.5 MBH more input than Dunkirk WPSB-6D (225 MBH against 187.5 MBH). Dunkirk WPSB-6D carries the higher published AFUE at 84.1%, against 84%.
Dunkirk WPSB-7D lists 67 lb more shipping weight than Dunkirk WPSB-6D (601 lb against 534 lb). The boiler water content differs: the Dunkirk WPSB-6D lists 11.7 gal, while the Dunkirk WPSB-7D lists 13.5 gal. The dimensions differs: the Dunkirk WPSB-6D lists 21" wide x 36-3/8 in. high x 26-1/2 in. deep, while the Dunkirk WPSB-7D lists 24-1/4" wide x 36-3/8 in. high x 26-1/2 in. deep.
Both records print the same domestic-hot-water arrangement (Heating-only boiler — domestic hot water comes from a separate indirect tank or water heater), gas connection (1/2 in. NPT gas inlet; 1-1/4 in. water return/supply (all models).), electrical requirement (120 V AC / 60 Hz / 1 phase, less than 12 A (15 A circuit recommended)) and fuel (Natural gas or propane), per the cited sources.
Dunkirk Boilers
The Dunkirk WPSB-6D is a current atmospheric cast-iron gas water boiler: 187.5 MBH natural-gas input (propane 175 MBH) for 157 MBH heating capacity and a 137 MBH net AHRI water rating at 84.1% AFUE, with 11.7 gallons of water content and a Fuel Smart Hydrostat control.
Dunkirk Boilers
The Dunkirk WPSB-7D is a current atmospheric cast-iron gas water boiler: 225 MBH natural-gas input (propane 210 MBH) for 188 MBH heating capacity and a 163 MBH net AHRI water rating at 84% AFUE, with 13.5 gallons of water content and a Fuel Smart Hydrostat control.
The Dunkirk WPSB-7D lists 225 MBH, against 187.5 MBH on the Dunkirk WPSB-6D, per the cited documentation.
The Dunkirk WPSB-6D carries the higher published AFUE at 84.1%, against 84%.
It ships at 601 lb against 534 lb for the Dunkirk WPSB-6D, per the cited sources.
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.