Dunkirk Boilers · WPSB Series 4
Dunkirk WPSB-6D
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.
Key figures
- Max input
- —
- Max CSA output
- —
- AFUE
- 84.1 %
- Min input
- —
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Dunkirk WPSB-6D in practice
The WPSB-6D is one of the seven natural-gas sizes in Dunkirk's current WPSB Series 4 line. Its AHRI-certified ratings row prints 187.5 MBH input, 157 MBH heating capacity and a 137 MBH net water rating (1.15 allowance) at 84.1% AFUE, with 11.7 gallons of water content; the product page lists the matching propane (DP) version at 175 MBH.
The boiler is atmospheric cast iron with an integral draft hood and automatic vent damper for low-clearance installations, chimney vented, connecting on 1-1/4 in. water return/supply and a 1/2 in. NPT gas inlet at 534 lb shipping. The control module is the Fuel Smart Hydrostat with temperature limit, low-water cut-off, boiler reset, circulator relay and domestic-hot-water input override, with a temperature LED display and diagnostic indicator lights.
Boilers.ca records the printed row for the WPSB-6D; no official Canadian-sales statement was found, so canadianStatus stays 'unknown', and gas, combustion and venting work belongs with a licensed contractor against the WPSB manual Rev. F.
Best suited to
- 187.5-MBH-class residential loads (157 MBH heating capacity)
- Chimney-vented replacements in low-clearance boiler rooms
- Systems pairing the boiler with an indirect water heater via the DHW override
Applicability and support
- Model number
- WPSB-6D
- Canadian availability
- unknown
- Production status
- current
- 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.
Specifications
Published specifications
Values as published by Dunkirk Boilers. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input | 187.5 MBH | Input per the official ratings table (sea level to 2,000 ft; reduce 4% per 1,000 ft above 2,000 ft). |
| Output | ||
| Heating capacity | 157 MBH | Heating capacity per the official ratings table (DOE test procedures). |
| Net AHRI water rating | 137 MBH | Net AHRI water rating based on a piping and pickup allowance of 1.15 per the official ratings table. |
| Efficiency | ||
| Efficiency (AFUE) | 84.1 % | AFUE per the WPSB Series 4 brochure ratings table. |
| Domestic hot water | ||
| Domestic hot water | Heating-only boiler — domestic hot water comes from a separate indirect tank or water heater | |
| Venting and air | ||
| Flue | — | Chimney-vented atmospheric boiler with an integral draft hood and automatic vent damper (product page). |
| Physical and connections | ||
| Boiler water content | 11.7 gal | Water content per the official ratings table. |
| Dimensions | 21" wide x 36-3/8 in. high x 26-1/2 in. deep | Cabinet dimensions per the official ratings table (A width shown; height and depth as printed for the line). |
| Shipping weight | 534 lb | Shipping weight per the official ratings table. |
| Gas connection | 1/2 in. NPT gas inlet; 1-1/4 in. water return/supply (all models). | As printed in the official ratings table connections block. |
| Electrical | ||
| Electrical | 120 V AC / 60 Hz / 1 phase, less than 12 A (15 A circuit recommended) | Per the official ratings table connections block. |
| Operating limits and other | ||
| Fuel | Natural gas or propane | Conversion kits are listed among the official options. |
Manuals
- WPSB Series 4 Brochure 240009711 (08/19/25) — ratings table240009711 (08/19/25)
- WPSB Boiler Manual Rev. F (240013090)240013090 Rev. F · 2025-09
Alerts documented for this model
None documented yet.
Frequently asked questions
What are the WPSB-6D's ratings?
187.5 MBH natural-gas input (propane 175 MBH), 157 MBH heating capacity and a 137 MBH net AHRI water rating at 84.1% AFUE per the Series 4 brochure.
Does the WPSB-6D need a chimney?
Yes — the WPSB is atmospheric with an integral draft hood and automatic vent damper, chimney vented.
What control does the WPSB-6D use?
The Fuel Smart Hydrostat module with temperature limit, low-water cut-off, boiler reset and circulator relay, plus a temperature LED display and diagnostic indicator lights.
Questions about the Dunkirk WPSB-6D?
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
- Dunkirk — WPSB Series 4 gas boiler (WPSB-6D ratings) · accessed September 9, 2026
- WPSB Series 4 Brochure 240009711 (08/19/25) · accessed September 9, 2026
- WPSB Boiler Manual Rev. F (240013090) · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.