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Bosch Thermotechnology · Series
The Buderus SB745WS is the larger stainless steel commercial condensing boiler block, discontinued, in four sizes (800, 1050, 1300, 1550) with 3,003 to 5,443 MBH natural-gas input, 2,846 to 5,029 MBH gross output and 348.7 to 501.9 US gallons of water. It appears on Bosch's US 'Discontinued Boilers' page.
Series facts
The SB745WS shares the SB625WS design - stainless steel condensing block with turbulators and a lightly pressurized combustion chamber - in four larger sizes. The installation manual's technical table lists 800 (3,003 MBH NG input, 2,846 gross output, 348.7 gal water), 1050 (3,754 / 3,529 / 368.5), 1300 (4,692 / 4,364 / 482.1) and 1550 (5,443 / 5,029 / 501.9), all at 80 psi maximum working pressure and 210 °F maximum working temperature.
The SB745WS has its own product page under Bosch's US 'Discontinued Boilers' section with the shared SB625WS/SB745WS installation and operating manuals and the UL-listed burner sheet. It is a boiler block requiring a field-supplied burner, and Boilers.ca notes that the later SSB family (series-bosch-ssb) is the current commercial condensing line. Bosch's documentation index also prints the section heading 'SB625WS / SB725WS' on one page; the installation manual, burner sheet and product page all use SB745WS, which Boilers.ca treats as the official name.
Highlights
Models
One canonical page per model with input, output and efficiency kept separate.
Bosch Thermotechnology
The Buderus SB745WS 800 is a discontinued commercial stainless steel condensing boiler block rated 3,003 MBH natural-gas input (21.4 GPH oil) with 2,846 MBH gross output and 348.7 US gal water capacity.
Bosch Thermotechnology
The Buderus SB745WS 1050 is a discontinued commercial stainless steel condensing boiler block rated 3,754 MBH natural-gas input (26.8 GPH oil) with 3,529 MBH gross output and 368.5 US gal water capacity.
Bosch Thermotechnology
The Buderus SB745WS 1300 is a discontinued commercial stainless steel condensing boiler block rated 4,692 MBH natural-gas input (33.5 GPH oil) with 4,364 MBH gross output and 482.1 US gal water capacity.
Bosch Thermotechnology
The Buderus SB745WS 1550 is a discontinued commercial stainless steel condensing boiler block rated 5,443 MBH natural-gas input (38.8 GPH oil) with 5,029 MBH gross output and 501.9 US gal water capacity.
| Specification | Buderus SB745WS 800 | Buderus SB745WS 1050 | Buderus SB745WS 1300 | Buderus SB745WS 1550 |
|---|---|---|---|---|
| input-min | — | — | — | — |
| input-max | — | — | — | — |
| output-max | — | — | — | — |
| afue | — | — | — | — |
| turndown | — | — | — | — |
| vent-max-3 | — | — | — | — |
| vent-max-2 | — | — | — | — |
| Weight of boiler | 1,890 kg | 2,167 kg | 2,680 kg | 3,100 kg |
Read the full comparison: Buderus SB745WS 800 vs SB745WS 1550 →
Read the full comparison: Buderus SB745WS 1050 vs SB745WS 1300 →
Read the full comparison: Buderus SB745WS 1300 vs SB745WS 1550 →
Read the full comparison: Buderus SB745WS 1050 vs SB745WS 1550 →
Error codes and alerts
No alerts documented for this series yet.
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 Bosch Thermotechnology boilers
No. It has a discontinued-product page on Bosch's US site and is not in the current commercial catalog; the Buderus SSB family is the current commercial condensing line.
One heading in the discontinued Buderus documentation index reads 'SB625WS / SB725WS', but the installation manual, the recommended-burners sheet and the discontinued-product page all use SB745WS. Boilers.ca uses SB745WS as the official model name and flags the index typo in research.
The 1550: 5,443 MBH natural-gas input, 5,029 MBH gross output and 501.9 US gallons of boiler water, per the installation manual technical table.
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 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.