Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
Boilers.ca is a brand of ROMA Heating & Cooling · Licensed gas contractor LGA0202903
Bosch Thermotechnology · Series
The first-generation Buderus SSB commercial condensing boilers were sold as six sizes - SSB85, SSB120, SSB160, SSB255, SSB399 and SSB512 - with ASME Section IV construction, 5:1 turndown and 96% AFUE on the smaller four. All six now sit in Bosch's US discontinued commercial-boiler literature library.
Series facts
AHRI certified ratings print 96% AFUE for SSB85, SSB120, SSB160 and SSB255. SSB399 and SSB512 print combustion efficiency (97.6% / 95.4%) and thermal efficiency (96.9% / 96.8%) instead of an AFUE row.
The SSB85, SSB120 and SSB160 are wall-hung ASME Section IV stainless steel condensing boilers rated 85,300 / 119,420 / 160,364 BTU/hr maximum input with 5:1 turndown, 96% AFUE and 1" water connections; the SSB255, SSB399 and SSB512 are the larger floor-standing blocks rated 255,900 / 399,000 / 512,000 BTU/hr. All six are documented in Bosch's US 'Discontinued Boilers' commercial archive and in the discontinued Buderus products documentation library.
These sizes are the predecessors of the current SSB Gen 1 and Gen 2 family (series-bosch-ssb): the current catalog carries only the SSB800, SSB1000 and SSB1000TL modules and their cascades, while the 85-512 sizes are no longer listed for sale. Boilers.ca keeps them as historical records so owners and service techs can still match a rating plate and find the right manual. The SSB85/120/160 service manual's lockout and blocking tables are also extracted in the batch-10 research files for code lookups.
Highlights
Models
One canonical page per model with input, output and efficiency kept separate.
Bosch Thermotechnology
The Buderus SSB85 is a discontinued wall-hung commercial/residential stainless steel condensing boiler rated 85,300 BTU/hr maximum input with 5:1 turndown, 96% AFUE and 69 MBH net rating.
Bosch Thermotechnology
The Buderus SSB120 is a discontinued wall-hung commercial/residential stainless steel condensing boiler rated 119,420 BTU/hr maximum input with 5:1 turndown, 96% AFUE and 96 MBH net rating.
Bosch Thermotechnology
The Buderus SSB160 is a discontinued wall-hung commercial/residential stainless steel condensing boiler rated 160,364 BTU/hr maximum input with 5:1 turndown, 96% AFUE and 129 MBH net rating.
Bosch Thermotechnology
The Buderus SSB255 is a discontinued floor-standing commercial/residential stainless steel condensing boiler rated 255,900 BTU/hr maximum input with 5:1 turndown, 96% AFUE and 206 MBH net rating.
Bosch Thermotechnology
The Buderus SSB399 is a discontinued floor-standing commercial/residential stainless steel condensing boiler rated 399,000 BTU/hr maximum input with 5:1 turndown, 96.9% AHRI thermal efficiency and 336 MBH net rating.
Bosch Thermotechnology
The Buderus SSB512 is a discontinued floor-standing commercial/residential stainless steel condensing boiler rated 512,000 BTU/hr maximum input with 5:1 turndown, 96.8% AHRI thermal efficiency and 430 MBH net rating.
| Specification | Buderus SSB85 | Buderus SSB120 | Buderus SSB160 | Buderus SSB255 | Buderus SSB399 | Buderus SSB512 |
|---|---|---|---|---|---|---|
| Input, minimum | 17.06 MBH | 23.884 MBH | 32.073 MBH | 51.18 MBH | 79.8 MBH | 102.4 MBH |
| Input, maximum | 85.3 MBH | 119.42 MBH | 160.364 MBH | 255.9 MBH | 399 MBH | 512 MBH |
| output-max | — | — | — | — | — | — |
| Efficiency (AFUE) | 96 % | 96 % | 96 % | 96 % | — | — |
| Turndown | 5:1 | 5:1 | 5:1 | 5:1 | 5:1 | 5:1 |
| vent-max-3 | — | — | — | — | — | — |
| vent-max-2 | — | — | — | — | — | — |
| weight | — | — | — | — | — | — |
Read the full comparison: Buderus SSB85 vs SSB120 →
Read the full comparison: Buderus SSB255 vs SSB399 →
Read the full comparison: Buderus SSB399 vs SSB512 →
Read the full comparison: Buderus SSB120 vs Buderus SSB160 →
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 Bosch Thermotechnology boilers
These six sizes are no longer in Bosch's current commercial catalog: they appear in the US 'Commercial Products - Discontinued' boiler archive and in the discontinued Buderus products documentation library. The current SSB products are the Gen 1 and Gen 2 SSB800, SSB1000 and SSB1000TL modules and cascades.
Bosch's US discontinued commercial-boiler library still serves the SSB85/120/160 installation and service manuals and the SSB255/399/512 installation manual and cut sheet. Boilers.ca links the live PDF URLs on each model record.
They are the same Buderus Stainless Steel Boiler family. The 85-512 sizes were the first commercial SSB offerings; the current catalog replaced them with the larger SSB800/1000/1000TL modules built as single units or factory cascades.
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.