Viessmann · Vitodens 100-W (legacy B1HA / B1KA and earlier)
Viessmann Vitodens 100-W WB1A 8-24
The Vitodens 100-W WB1A 8-24 is the smaller of the two WB1A boilers: 29 to 80 MBH natural gas input at 95.1% AFUE in a 95 lb (43 kg) wall-hung cabinet.
Key figures
- Max input
- 80 MBH
- Max CSA output
- —
- AFUE
- 95.1 %
- Min input
- 29 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Viessmann Vitodens 100-W WB1A 8-24 in practice
The WB1A 8-24 is the first-generation Vitodens 100-W documented in Viessmann Canada's historic manuals: a natural gas-fired wall-mounted condensing boiler rated 29-80 MBH (8.5-23.4 kW) input, 26-72 MBH (7.6-21 kW) output and a 63 MBH Net I=B=R rating at 95.1% AFUE.
It weighs 95 lb (43 kg) with 0.82 USG of boiler water and a 45 psig maximum operating pressure, measuring 400 x 340 x 700 mm (15.7 x 13.4 x 27.6 in). The technical data manual prints natural gas ratings only, and the unit is suitable for high-altitude operation with the adjustments described in its documentation.
Best suited to
- Owners of existing WB1A 8-24 units looking up printed ratings
- Small residential loads from 29 MBH on natural gas
- Documentation for the earliest Vitodens 100-W generation
Applicability and support
- Model number
- WB1A 8-24
- 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 (natural gas) | 29 MBH | 8.5 kW, per the technical data manual |
| CSA input, maximum (natural gas) | 80 MBH | 23.4 kW, per the technical data manual |
| Output | ||
| CSA output / DOE heating capacity | 26-72 MBH | 7.6-21 kW, based on 140°F / 120°F supply/return |
| Net I=B=R rating | 63 MBH | Based on piping and pick-up allowance of 1.15. |
| Efficiency | ||
| Efficiency (AFUE) | 95.1 % | 95.1% AFUE on both WB1A models per the technical data manual. |
| Physical and connections | ||
| Weight | 95 lb | 43 kg |
| Overall width | 400 mm | 15.7 in |
| Overall depth | 340 mm | 13.4 in |
| Overall height | 700 mm | 27.6 in |
| Operating limits and other | ||
| Fuel | Natural gas | The WB1A technical data manual prints natural-gas ratings only; minimum supply pressure 4 in. w.c. |
| Boiler water content | 0.82 USG | 3.1 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 WB1A 8-24 rated at?
29-80 MBH (8.5-23.4 kW) natural gas input, 26-72 MBH (7.6-21 kW) output, a 63 MBH Net I=B=R rating and 95.1% AFUE.
Does the WB1A run on propane?
The WB1A technical data manual (doc 5347 963 v1.1) prints natural gas ratings only. The later WB1B generation added printed liquid propane ratings.
What manual covers the WB1A 8-24?
The Vitodens 100-W WB1A technical data manual (doc 5347 963 v1.1, 10/2007) and the WB1 installation/service instructions, both linked on this record and kept in Viessmann Canada's historic manuals.
Questions about the Viessmann Vitodens 100-W WB1A 8-24?
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 WB1A 8-24 vs WB1A 8-30Comparison
- 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 8-30Same series
- Viessmann Vitodens 100-W WB1B 26Same series
- Viessmann Vitodens 100-W WB1B 35Same series
- Vitodens 100-W (legacy B1HA / B1KA and earlier) series hub
- Buying guide
Sources and verification
- Technical Data Manual — Vitodens 100-W WB1A Series, doc 5347 963 v1.1 · 5347 963 v1.1 · 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.