Dunkirk DXL
Model Number: DXL
DXL is an archived Dunkirk cast-iron gas hot-water boiler, replaced by the DXL-K.
Technical Specifications
Source: manufacturer product data · checked Sep 27, 2026
Prices depend on sizing, venting and piping in your home, so we quote every installation.
Discontinued: discontinued per manufacturer. If you already own one, we can still service it where parts are available. For a new install, compare current Dunkirk models or every brand's lineup.
Sizing: the right size comes from a room-by-room heat-loss calculation, not the size of the old boiler or a rule of thumb. Oversized boilers short-cycle and waste fuel; steam systems are sized to the connected radiation instead. See how we approach boiler installation.
Home-Specific Operating Cost Review
No guaranteed annual savings or payback period
Historical Use
Fuel consumption and weather
Current Rates
Utility and delivered-fuel prices
System Design
Load, piping, controls, and temperatures
Full Specifications
- Model Number
- DXL
- Efficiency (AFUE)
- 83.5%
- Boiler Type
- Hot Water Boiler
- Fuel
- natural gas
- Venting
- natural draft
- In Production
- No — discontinued per manufacturer
Specifications sourced from the manufacturer product data, checked Sep 27, 2026.
Ideal For
Owners of an existing DXL weighing repair against replacement
Expert Review: Dunkirk DXL
DXL is a discontinued Dunkirk cast-iron gas hot-water boiler. Dunkirk's archived product page states that it is no longer available, and the current replacement is the DXL-K.
The DXL used cast-iron sections with natural-draft chimney venting and was listed at up to 83.5% AFUE. If you own one, a contractor can check the condition of the sections, the chimney and parts availability before recommending repair or replacement.
When replacing it, size the new boiler from a heat-loss calculation rather than copying the old unit's input.
Key Features & Technology
Dunkirk's archived product page states the DXL is no longer available.
Cast-iron sections, natural-draft venting.
Efficiency was listed at up to 83.5% AFUE.
The current replacement is the DXL-K (59–235 MBH, 84% AFUE).
Advantages
- Familiar cast-iron design that many technicians already service.
- A current successor, the DXL-K, exists for replacements.
Considerations
- Discontinued: new units are no longer sold.
- Parts availability should be confirmed before repairing an older unit.
- Warranty terms for existing units depend on the original certificate and install date.
Sizing & Installation Notes
Hot water boilers like the DXL are sized from a room-by-room heat-loss calculation. We never match the old boiler's size — oversized units short-cycle, waste fuel and wear out years early.
Every Dunkirk installation starts with a free in-home assessment covering the heat-loss calculation, venting and chimney condition, and gas or oil supply sizing. Learn more about our boiler installation process, or see current rebate and incentive programs that may apply.
Warranty & Protection
Parts Warranty
See spec sheet
Heat Exchanger
See spec sheet
Our Guarantee
100% Satisfaction
All Dunkirk boiler installations by Home+ Air & Heat include our 1-year workmanship warranty, covering labor and any installation-related issues.
Compare the Dunkirk Lineup
| Model | Efficiency | BTU Range | Fuel | Heat Exchanger Warranty |
|---|---|---|---|---|
| DXL (this model) | 83.5% AFUE | Various sizes available | natural gas | — |
| Q95M | 95% AFUE | 80k - 200k BTU | natural gas/propane | 15-yr limited |
| WPSB Series 4 | 84.1% AFUE | 75k - 299k BTU | natural gas | 20-yr non-prorated |
| XEB Series 4 | 84.4% AFUE | 43k - 188k BTU | natural gas | 20-yr non-prorated |
| Royal HE | 95.2% AFUE | 80k - 200k BTU | natural gas/propane | 10 years |
| DXL-K | 84% AFUE | 59k - 235k BTU | natural gas | 20-yr non-prorated |
| Royal CO (combi) | 95.2% AFUE | 80k - 200k BTU | natural gas/propane | 10 years |
| PSB | 82.7% AFUE | 75k - 299k BTU | natural gas | 12-yr limited |
See the full Dunkirk brand page for lineup context, or browse the Best Hot Water Boilers 2027 guide to compare across brands.
Frequently Asked Questions
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