Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
Stepping from the Ultra 230 to the 299 adds 69 MBH of input (230 to 299) and lifts DOE heating capacity from 207 to 270 MBH, but efficiency drops from 94.1% to 92.5% AFUE, venting becomes 4"-only, and connections grow to 1-1/4" NPT with 3/4" gas.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Weil-McLain Ultra 230 | Weil-McLain Ultra 299 |
|---|---|---|
| Input, maximum | 230 MBH | 299 MBH |
| Input, minimum | 46 MBH | 62 MBH |
| DOE heating capacity | 207 MBH | 270 MBH |
| Net AHRI water rating | 180 MBH | 235 MBH |
| Efficiency (AFUE) | 94.1 % | 92.5 % |
| Weight | 246 lb | 297 lb |
| Boiler water content | 1.57 gal | 2.1 gal |
| Venting | 3" or 4" PVC, CPVC, polypropylene or stainless steel (Category IV) | 4" PVC, CPVC, polypropylene or stainless steel (Category IV); 4" pipe only on the 299 |
The Ultra 299 is a different size class within Series 4: input rises from 230 to 299 MBH, DOE heating capacity from 207 to 270 MBH and the net AHRI rating from 180 to 235 MBH, with low fire stepping from 46 to 62 MBH.
The trade-off is efficiency and installation: the 299 rates 92.5% AFUE against the 230's 94.1%, requires 4" venting only (the 230 can run 3" to 30 ft or 4" to 100 ft), and steps supply and return tappings to 1-1/4" NPT with a 3/4" NPT gas connection and 1-1/2" minimum pipe.
Water content grows from 1.57 to 2.1 gallons and weight from 246 to 297 lb. Because the 230 is the most efficient Ultra, a load that fits under 207 MBH of DOE output is better served by the 230; the 299 exists for loads that genuinely exceed it.
Weil-McLain
The Ultra 230 is the most efficient model in the Ultra line at 94.1% AFUE — the figure behind the CA page's up-to-94.1% claim — with 230 MBH input, a 46 MBH low fire and 3"-or-4" venting.
Weil-McLain
The Ultra 299 steps up to 4" venting and 1-1/4" tappings: 299 MBH input, a 62 MBH low fire, 270 MBH DOE heating capacity and 92.5% AFUE in the largest Ultra cabinet.
Weil-McLain's Series 4 ratings step down at the top of the range: 94.1% AFUE on the 230 against 92.5% on the 299.
Venting becomes 4" only, supply and return tappings step to 1-1/4" NPT, gas to 3/4" NPT, and minimum recommended pipe to 1-1/2".
When the heat-loss calculation and system demand exceed the 230's 207 MBH of DOE heating capacity on a design day.
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 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.