Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The Dunkirk XEB-5 and Dunkirk XEB-6 are both non-condensing boilers in the Dunkirk Boilers XEB Series 4 line. The Dunkirk XEB-5 is rated 150 MBH input, 127 MBH heating capacity and 84% AFUE, and the Dunkirk XEB-6 is rated 187.5 MBH input, 158 MBH heating capacity and 84% AFUE. Dunkirk XEB-6 lists 37.5 MBH more input than Dunkirk XEB-5 (187.5 MBH against 150 MBH). Both list the same published AFUE of 84%. Dunkirk XEB-6 lists 61 lb more shipping weight than Dunkirk XEB-5 (431 lb against 370 lb).
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Dunkirk XEB-5 | Dunkirk XEB-6 |
|---|---|---|
| Input | 150 MBH | 187.5 MBH |
| Heating capacity | 127 MBH | 158 MBH |
| Net AHRI water rating | 109 MBH | 135 MBH |
| Efficiency (AFUE) | 84 % | 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 | 5.5 gal | 6.75 gal |
| Shipping weight | 370 lb | 431 lb |
| Dimensions | 20-3/4" wide x 29 in. high x 23-1/4 in. deep | 24" wide x 29 in. high x 23-1/4 in. deep |
| Gas connection | 1/2 in. NPT gas inlet; 1-1/4 in. water return/supply. | 1/2 in. NPT gas inlet; 1-1/4 in. water return/supply. |
| 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 |
| Flue | 4" chimney / 3" side wall | 4" chimney / 4" side wall |
Published ratings: the Dunkirk XEB-5 is rated 150 MBH input, 127 MBH heating capacity and 84% AFUE; the Dunkirk XEB-6 is rated 187.5 MBH input, 158 MBH heating capacity and 84% AFUE. Dunkirk XEB-6 lists 37.5 MBH more input than Dunkirk XEB-5 (187.5 MBH against 150 MBH). Both list the same published AFUE of 84%.
Dunkirk XEB-6 lists 61 lb more shipping weight than Dunkirk XEB-5 (431 lb against 370 lb). The boiler water content differs: the Dunkirk XEB-5 lists 5.5 gal, while the Dunkirk XEB-6 lists 6.75 gal. The dimensions differs: the Dunkirk XEB-5 lists 20-3/4" wide x 29 in. high x 23-1/4 in. deep, while the Dunkirk XEB-6 lists 24" wide x 29 in. high x 23-1/4 in. deep. The flue differs: the Dunkirk XEB-5 lists 4" chimney / 3" side wall, while the Dunkirk XEB-6 lists 4" chimney / 4" side wall.
Both records print the same AFUE (84%), 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.) and electrical requirement (120 V AC / 60 Hz / 1 phase, less than 12 A (15 A circuit recommended)), per the cited sources.
Dunkirk Boilers
The Dunkirk XEB-5 is a current induced-draft cast-iron gas water boiler: 150 MBH input for 127 MBH heating capacity and a 109 MBH net AHRI water rating at 84% AFUE, with 5.5 gallons of water content, a 4" chimney / 3" side wall vent option and a Honeywell recessed control at 370 lb shipping.
Dunkirk Boilers
The Dunkirk XEB-6 is a current induced-draft cast-iron gas water boiler: 187.5 MBH input for 158 MBH heating capacity and a 135 MBH net AHRI water rating at 84% AFUE, with 6.75 gallons of water content, a 4" chimney / 4" side wall vent option and a Honeywell recessed control at 431 lb shipping.
The Dunkirk XEB-6 lists 187.5 MBH, against 150 MBH on the Dunkirk XEB-5, per the cited documentation.
Both list the same AFUE of 84%.
It ships at 431 lb against 370 lb for the Dunkirk XEB-5, 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.