Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Weil-McLain · Series
The Ultra is Weil-McLain's floor- or wall-mountable cast-aluminum condensing boiler, current in both Canada and the US as Series 4: Canadian residential sizes 80 to 399 MBH with 5:1 modulation, U-Control diagnostics and up to 94.1% AFUE (the 230 model).
Series facts
CA page lists AFUE up to 94.1%, which is the Ultra 230's rating; Series 4 model ratings are 93.5-94.1% AFUE, and the 399's asterisked 91.7% is combustion efficiency, not AFUE.
The Ultra is a condensing boiler built around a nano-coated cast aluminum heat exchanger that modulates over a 5:1 range — the CA page notes "5 to 1 modulation, floor or wall mount, includes water inhibitor and boiler pump." The US Series 4 literature (manual 550-100-440/1025, brochure 0925) lists six sizes — Ultra 80, 105, 155, 230, 299 and 399 — with DOE AFUE from 93.5% (80) to 94.1% (230), and the 399's asterisked 91.7% figure is combustion efficiency rather than an AFUE rating.
Weil-McLain Canada's residential Ultra page lists seven sizes: the six Series 4 sizes plus a 310 MBH model (output 289 MBH) that appears in no current US Series 4 document — 310 was a Series 1-3 era size, and the CA page's "up to 94.1%" AFUE line is the 230's rating. Boilers.ca records the 310 model against the CA page and flags the discrepancy, because the Series 4 manual's rating tables stop at 399 with no 310.
Venting is Category IV with max lengths that vary by size: 2" or 3" piping to 100 ft on the 80/105, 3" only to 100 ft on the 155, 4" to 100 ft (or 3" to 30 ft) on the 230, and 4" to 100 ft on the 299/399. No altitude modifications are required from sea level to 5,500 ft, with a control high-altitude selection above that.
Highlights
Residential: 12-year heat exchanger replacement / 2-year all other parts; commercial: 10-year heat exchanger / 1-year parts, per the CA product page (CA page omits the 5-year parts-with-registration upgrade shown in the US Series 4 brochure).
Models
One canonical page per model with input, output and efficiency kept separate.
Weil-McLain
The Ultra 80 is the smallest Series 4 Ultra: 80 MBH input with a 16 MBH low fire, 71 MBH DOE heating capacity and 93.5% AFUE from a nano-coated cast aluminum condensing block.
Weil-McLain
The Ultra 105 adds 25 MBH of input over the 80: 105 MBH maximum, 21 MBH low fire, 94 MBH DOE heating capacity and 94.0% AFUE from the same nano-coated cast aluminum Series 4 platform.
Weil-McLain
The Ultra 155 is the first Series 4 Ultra to require 3" venting: 155 MBH input, 31 MBH low fire, 139 MBH DOE heating capacity and 94.0% AFUE from the cast aluminum condensing block.
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
The Ultra 310 is listed on weil-mclain.ca at 310 MBH input and 289 MBH output, but it appears in no current US Series 4 document — Boilers.ca records the size from the CA page while flagging that manual 550-100-440/1025 does not cover it.
Weil-McLain
The Ultra 399 is the largest Series 4 Ultra: 399 MBH input from an 80 MBH low fire, with the US table's asterisked 91.7% combustion efficiency and 364 MBH gross output — the manual's footnote says those figures are not an AFUE.
| Specification | Weil-McLain Ultra 80 | Weil-McLain Ultra 105 | Weil-McLain Ultra 155 | Weil-McLain Ultra 230 | Weil-McLain Ultra 299 | Weil-McLain Ultra 310 | Weil-McLain Ultra 399 |
|---|---|---|---|---|---|---|---|
| Input, minimum | 16 MBH | 21 MBH | 31 MBH | 46 MBH | 62 MBH | — | 80 MBH |
| Input, maximum | 80 MBH | 105 MBH | 155 MBH | 230 MBH | 299 MBH | 310 MBH | 399 MBH |
| DOE heating capacity | 71 MBH | 94 MBH | 139 MBH | 207 MBH | 270 MBH | 289 MBH | 364 MBH |
| Efficiency (AFUE) | 93.5 % | 94 % | 94 % | 94.1 % | 92.5 % | — | — |
| Turndown | 5:1 | 5:1 | 5:1 | 5:1 | 5:1 | 5:1 | 5:1 |
| vent-max-3 | — | — | — | — | — | — | — |
| vent-max-2 | — | — | — | — | — | — | — |
| Weight | 199 lb | 207 lb | 234 lb | 246 lb | 297 lb | — | 297 lb |
Read the full comparison: Weil-McLain Ultra 80 vs Ultra 105 →
Read the full comparison: Weil-McLain Ultra 105 vs Ultra 155 →
Read the full comparison: Weil-McLain Ultra 155 vs Ultra 230 →
Read the full comparison: Weil-McLain Ultra 230 vs Ultra 299 →
Read the full comparison: Weil-McLain Ultra 299 vs Ultra 399 →
Read the full comparison: Bosch Greenstar ZBR 42-3A vs Weil-McLain Ultra 155 →
Error codes and alerts
Manuals
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.
Services for Weil-McLain boilers
Yes. The Ultra is current on both weil-mclain.ca (residential menu) and weil-mclain.com as Series 4, with a 2025 brochure and an October 2025 boiler manual. It is not discontinued in either country.
Weil-McLain Canada's Ultra page lists 310 MBH among its input sizes, but no current US Series 4 document — manual 550-100-440/1025, the brochure or the product page — includes a 310 size. It appears to be a Series 1-3 era size still listed on the CA page.
The Ultra's U-Control module shows text fault names and screen messages rather than numeric error codes. The Series 4 boiler manual documents the fault list and lockout history screens.
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
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.