Viessmann · Vitocrossal (legacy CA3/CT3 and earlier CM2 generations)
Viessmann Vitocrossal 300 CT3-89
The Vitocrossal 300 CT3-89 is the largest CT3 boiler: 3361 MBH input (985 kW), 3252 MBH output and 96.7% combustion and thermal efficiency — the top of the range.
Key figures
- Max input
- —
- Max CSA output
- —
- AFUE
- —
- Min input
- —
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Viessmann Vitocrossal 300 CT3-89 in practice
The CT3-89 tops the CT3 range at 3361 MBH (985 kW) input and 3252 MBH (953 kW) output, printing the range's lowest efficiency rows at 96.7% combustion and thermal efficiency. It shares the 951 mm shell, 12 in. vent pipe and 2,235 mm height with the CT3-72.
The boiler shell weighs 3,014 lb (1,370 kg) and the complete unit 3,344 lb (1,520 kg) — the heaviest in the range — with 221.9 USG (840 L) of boiler water and a 2,289 x 951 x 2,235 mm (90 x 37½ x 88 in) shipping envelope.
Best suited to
- Existing CT3-89 installations needing printed ratings
- The largest CT3 loads at up to 3361 MBH input
- Documentation for the top CT3 size
Applicability and support
- Model number
- CT3-89
- 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 | ||
| Input | 3,361 MBH | 985 kW, per the technical data manual |
| Output | ||
| Output | 3,252 MBH | 953 kW; tested to AHRI BTS-2000. |
| Efficiency | ||
| Combustion efficiency | 96.7 % | Per the printed rating table. |
| Thermal efficiency | 96.7 % | Per the printed rating table. |
| Venting and air | ||
| Vent pipe internal diameter | 12 in | 301 mm per the technical data manual. |
| Physical and connections | ||
| Weight, boiler shell | 3,014 lb | 1370 kg |
| Overall weight (with insulation and control, less burner) | 3,344 lb | 1520 kg |
| Boiler length as shipped (door removed) | 2,289 mm | Printed as 90 in |
| Width 1 (maximum shell width) | 951 mm | Printed as 37½ in |
| Maximum height | 2,235 mm | Printed as 88 in |
| Operating limits and other | ||
| Fuel | Natural gas or liquid propane | Gas-fired condensing boiler; maximum supply temperature 210°F (99°C). |
| Boiler water content | 221.9 USG | Per the technical data manual. |
| Maximum operating pressure | 30 psig | 207 kPa; maximum operating temperature 210°F (99°C). |
| Boiler supply / return | Per model | Supply and return connections 2½ to 5 in. depending on size; boiler drain 1 in. |
Manuals
- Technical Data Manual — Vitocrossal 300 CT3 Series, doc 5285 871 - 055285 871 - 05 · 2016-01
- Installation Instructions — Vitocrossal 300 CT3, rev 0303 · 2015-10
- Service Instructions — Vitocrossal 300 CT3, rev 0404 · 2016-01
- Operating Instructions — Vitocrossal 300 CT3, rev 0202 · 2015-10
Alerts documented for this model
None documented yet.
Frequently asked questions
What is the CT3-89 rated at?
3361 MBH (985 kW) input and 3252 MBH (953 kW) output, with 96.7% combustion efficiency and 96.7% thermal efficiency.
How much water does the CT3-89 hold?
221.9 USG (840 L) of boiler water, the highest in the CT3 range, with 383.2 ft² (35.6 m²) of water-cooled heat exchanger surface.
What are the CT3-89 connections?
5 in. boiler supply and return, 4 in. second boiler return, 2½ in. safety supply, 1 in. boiler drain and a 12 in. internal vent pipe.
Questions about the Viessmann Vitocrossal 300 CT3-89?
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 Vitocrossal 300 CT3-72 vs CT3-89Comparison
- Viessmann Vitocrossal 300 CT3-17Same series
- Viessmann Vitocrossal 300 CT3-22Same series
- Viessmann Vitocrossal 300 CT3-28Same series
- Viessmann Vitocrossal 300 CT3-37Same series
- Viessmann Vitocrossal 300 CT3-46Same series
- Viessmann Vitocrossal 300 CT3-57Same series
- Viessmann Vitocrossal 300 CT3-72Same series
- Vitocrossal (legacy CA3/CT3 and earlier CM2 generations) series hub
- Buying guide
Sources and verification
- Technical Data Manual — Vitocrossal 300 CT3 Series, doc 5285 871 - 05 · 5285 871 - 05 · 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.