Viessmann · Vitodens 100-W (legacy B1HA / B1KA and earlier)
Viessmann Vitodens 100-W WB1B 35
The Vitodens 100-W WB1B 35 is the larger WB1B boiler: 37 to 118 MBH NG/LPG input at 94.0% AFUE in the same 78 lb (34.1 kg) cabinet.
Key figures
- Max input
- 118 MBH
- Max CSA output
- —
- AFUE
- 94 %
- Min input
- 37 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Viessmann Vitodens 100-W WB1B 35 in practice
The WB1B 35 raises the second-generation 100-W to 118 MBH: 37-118 MBH (10.8-34.6 kW) NG/LPG input, 34-108 MBH (9.9-31.6 kW) output and a 94 MBH Net I=B=R rating at 94.0% AFUE.
Weight, water content, pressure rating and dimensions match the WB1B 26 — 78 lb (34.1 kg), 0.87 USG, 45 psig and 400 x 360 x 725 mm. The WB1B generation is heating-only; a CombiPLUS version of the WB1B with on-demand DHW is also documented in Viessmann Canada's historic manuals.
Best suited to
- Owners of existing WB1B 35 units looking up printed ratings
- Residential loads between the WB1B 26 and the B1HA 35, 125
- Documentation for the larger WB1B size
Applicability and support
- Model number
- WB1B 35
- Canadian availability
- historical
- Production status
- discontinued
- 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 Viessmann. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| CSA input, minimum (NG/LPG) | 37 MBH | 10.8 kW, per the technical data manual |
| CSA input, maximum (NG/LPG) | 118 MBH | 34.6 kW, per the technical data manual |
| Output | ||
| CSA output / DOE heating capacity | 34-108 MBH | 9.9-31.6 kW, based on 140°F / 120°F supply/return |
| Net I=B=R rating | 94 MBH | Based on piping and pick-up allowance of 1.15. |
| Efficiency | ||
| Efficiency (AFUE) | 94 % | 94.0% AFUE on both WB1B models per the technical data manual. |
| Physical and connections | ||
| Weight | 78 lb | 34.1 kg; shipping weight 95 lb (43 kg). |
| Overall width | 400 mm | 15¾ in |
| Overall depth | 360 mm | 14⅛ in |
| Overall height | 725 mm | 28½ in |
| Operating limits and other | ||
| Fuel | Natural gas or liquid propane | NG minimum supply pressure 4 in. w.c.; LPG 10 in. w.c. |
| Boiler water content | 0.87 USG | 3.3 L. |
| Maximum operating pressure | 45 psig | 3 bar at 210°F (99°C). |
| Boiler heating supply / return | ¾ in. NPTM | Gas supply ¾ in. NPTF. |
Manuals
- Technical Data Manual — Vitodens 100-W B1HA Series and B1KA Combi Boiler, doc 5784 566 - 125784 566 - 12 · 2025-04
- Installation and Service Instructions — Vitodens 100-W B1HA/B1KA, rev 2222 · 2025-08
- Technical Data Manual — Vitodens 100-W WB1A Series, doc 5347 963 v1.15347 963 v1.1 · 2007-10
- Technical Data Manual — Vitodens 100-W WB1B Series, doc 5369 277 v1.55369 277 v1.5 · 2010-01
Alerts documented for this model
None documented yet.
Frequently asked questions
What is the WB1B 35 rated at?
37-118 MBH (10.8-34.6 kW) NG/LPG input, 34-108 MBH (9.9-31.6 kW) output, a 94 MBH Net I=B=R rating and 94.0% AFUE.
How does the WB1B 35 differ from the WB1B 26?
Only the firing range: 37-118 vs 37-91 MBH input and 34-108 vs 34-83 MBH output, in the same 78 lb cabinet.
Was there a combi version of the WB1B?
Yes — Viessmann Canada's historic manuals list a WB1B CombiPLUS version with its own technical data manual and instructions; this record covers the standard WB1B 35.
Questions about the Viessmann Vitodens 100-W WB1B 35?
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.
Compare and explore
- Viessmann Vitodens 100-W WB1B 26 vs WB1B 35Comparison
- Viessmann Vitodens 100-W B1HA 26, 94Same series
- Viessmann Vitodens 100-W B1HA 35, 125Same series
- Viessmann Vitodens 100-W B1KA 35, 125Same series
- Viessmann Vitodens 100-W WB1A 8-24Same series
- Viessmann Vitodens 100-W WB1A 8-30Same series
- Viessmann Vitodens 100-W WB1B 26Same series
- Vitodens 100-W (legacy B1HA / B1KA and earlier) series hub
- Buying guide
Sources and verification
- Technical Data Manual — Vitodens 100-W WB1B Series, doc 5369 277 v1.5 · 5369 277 v1.5 · accessed September 9, 2026
- Viessmann Canada — Historic manuals · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.