Bosch Thermotechnology · Buderus SSB (85-512, discontinued)
Buderus SSB399
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.
Key figures
- Max input
- 399 MBH
- Max CSA output
- —
- AFUE
- —
- Min input
- 79.8 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Buderus SSB399 in practice
Best suited to
Applicability and support
- Model number
- SSB399
- 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 Bosch Thermotechnology. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input, maximum | 399 MBH | 399,000 BTU/hr; AHRI certified rating. |
| Input, minimum | 79.8 MBH | 79,800 BTU/hr. |
| Output | ||
| Gross output (AHRI) | 386 MBH | |
| Net rating (AHRI) | 336 MBH | |
| Efficiency | ||
| Combustion efficiency (AHRI) | 97.6 % | |
| Thermal efficiency (AHRI) | 96.9 % | |
| Venting and air | ||
| Vent/air intake connections | 4" (100 mm) | CPVC, PVC, PP, PP Flex and stainless steel AL29-4C (IPEX type IIA and IIB). |
| Physical and connections | ||
| Weight (dry) | 220 lb | 100 kg. |
| Dimensions (W × H × D) | 23 31/32 × 61 9/16 × 21 21/32 in (609 × 1564 × 550 mm) | |
| Surface heat exchanger | 27.2 sq ft (2.5 m²) | |
| Noise rating | 47 dB | |
| Maximum allowable working pressure (MAWP) | 80 psi | 80 psi (5.5 bar). |
| Maximum operating temperature | 194 °F | 90 °C. |
| Operating limits and other | ||
| Turndown | 5:1 | |
| Heat exchanger | Stainless steel condensing heat exchanger | ASME Section IV construction; CSA, ASME and AHRI listed. |
| Gas connection | 1" | |
| Water connections | 1 1/2" | |
| Fuel | Natural gas or propane | Propane requires conversion with the supplied kit. |
Manuals
Alerts documented for this model
Questions about the Buderus SSB399?
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
- Bosch Home Comfort US — Commercial Products - Discontinued: Discontinued Boilers · accessed September 9, 2026
- SSB255/399/512 Installation Instructions (6720818454) · accessed September 9, 2026
- Buderus SSB Stainless Steel Boiler Brochure (75h995352, 08.2017) · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.