Pennco FSB-6
The Pennco FSB-6 is the largest FSB size and the only row listing a 4-inch sidewall vent: 187.5 MBH input with 158 MBH heating capacity and a 135 MBH net water rating at 84% AFUE, vented through a 4" chimney or 4" sidewall connection.
Key figures
- Max input
- 187.5 MBH
- Max CSA output
- —
- AFUE
- 84 %
- Min input
- —
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Pennco FSB-6 in practice
The Pennco FSB-6 is a cast-iron gas water boiler rated at 187.5 MBH input. Its row in the FSB sell sheet prints 158 MBH heating capacity, a 135 MBH net water rating (1.15 piping and pickup allowance) and 84% AFUE, with a 4" chimney connection and a 4" sidewall option, a 24"-wide cabinet and an approximate weight of 431 lb.
The boiler uses a cast-iron heat exchanger with cast-iron push nipples — the sell sheet notes the sections and push nipples expand at the same rate when heated, maintaining a water-tight seal without gaskets — and a control that delays the burner start until residual heat has been transferred. Optional equipment includes natural gas or propane operation, a Fill-Trol and a thimble, and the boiler is design certified for installation on a noncombustible floor and tested for 50 PSI ASME working pressure.
Boilers.ca documents this size at model level from the sell sheet and links the published Series 4 IOM. Gas, venting and electrical work belongs with a licensed contractor. No official Canadian-sales statement was found, so canadianStatus stays 'unknown'.
Best suited to
- 187.5 MBH residential heat-loss loads
- Installations that may use sidewall venting instead of a chimney
- Owners wanting the push-nipple cast-iron section assembly
Applicability and support
- Model number
- FSB-6
- Canadian availability
- unknown
- Production status
- current
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Series terms
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 Pennco. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input | 187.5 MBH | Input per the FSB sell sheet ratings table. |
| Output | ||
| Heating capacity | 158 MBH | Heating capacity per the FSB sell sheet; based on DOE test procedures. |
| Net water rating | 135 MBH | Net water rating per the FSB sell sheet, based on a piping and pickup allowance of 1.15. |
| Efficiency | ||
| Efficiency (AFUE) | 84 % | AFUE per the FSB sell sheet ratings table (FSB-2 84.4%, FSB-3 through FSB-6 84%). |
| Domestic hot water | ||
| Domestic hot water | Heating-only boiler — domestic hot water comes from a separate indirect tank or water heater | |
| Venting and air | ||
| Venting (chimney / sidewall) | 4" chimney / 4" sidewall | Chimney and sidewall vent sizes per the FSB sell sheet ratings table; a thimble is an optional accessory. |
| Venting | Chimney or sidewall vented | The sell sheet notes the boiler is design certified for installation on a noncombustible floor and tested for 50 PSI ASME working pressure. |
| Physical and connections | ||
| Approx. shipping weight | 431 lb | Approximate weight per the FSB sell sheet ratings table. |
| Dimensions (width × height × depth) | 24" × 29" × 23-1/4" | FSB dimension values; height and depth are common across the line. |
| Supply/return tappings | 1-1/4" supply and return tappings | Water connection sizes per the FSB sell sheet. |
| Gas connection | 1/2" gas inlet | Gas inlet per the FSB sell sheet. |
| Operating limits and other | ||
| Control | Control delays burner start until residual heat is transferred | The control monitors water temperature and delays the burner starting until residual heat has been transferred, maximizing efficiency by firing only when needed. |
| Fuel | Natural gas or propane | The sell sheet lists 'Natural Gas or Propane' under optional equipment. |
Manuals
Frequently asked questions
What are the Pennco FSB-6's ratings?
187.5 MBH input, 158 MBH heating capacity, a 135 MBH net water rating and 84% AFUE with a 4" chimney or 4" sidewall vent per the FSB sell sheet.
Can the FSB-6 be sidewall vented?
The FSB ratings table lists a 4" sidewall option for this size alongside the 4" chimney connection; a thimble is available as an accessory.
Questions about the Pennco FSB-6?
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
- Pennco — FSB Series product page · accessed September 9, 2026
- Pennco FSB Sell Sheet 08-19-25 (PDF) · accessed September 9, 2026
- Pennco FSB Series 4 IOM Rev. A (PDF) · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.