Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
Pennco FSB-4 and Pennco FSB-5 are two non-condensing boilers from the Pennco FSB Series line. Published ratings: Pennco FSB-4 at 112.5 MBH input, 95 MBH heating capacity and 84% AFUE; Pennco FSB-5 at 150 MBH input, 127 MBH heating capacity and 84% AFUE. Pennco FSB-5 lists 37.5 MBH more input than Pennco FSB-4 (150 MBH against 112.5 MBH). Both list the same published AFUE of 84%. Pennco FSB-5 lists 48 lb more shipping weight than Pennco FSB-4 (370 lb against 322 lb).
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Pennco FSB-4 | Pennco FSB-5 |
|---|---|---|
| Input | 112.5 MBH | 150 MBH |
| Heating capacity | 95 MBH | 127 MBH |
| Net water rating | 82 MBH | 109 MBH |
| Efficiency (AFUE) | 84 % | 84 % |
| Domestic hot water | Heating-only boiler — domestic hot water comes from a separate indirect tank or water heater | Heating-only boiler — domestic hot water comes from a separate indirect tank or water heater |
| Approx. shipping weight | 322 lb | 370 lb |
| Dimensions (width × height × depth) | 17-1/2" × 29" × 23-1/4" | 20-3/4" × 29" × 23-1/4" |
| Venting | Chimney or sidewall vented | Chimney or sidewall vented |
| Supply/return tappings | 1-1/4" supply and return tappings | 1-1/4" supply and return tappings |
| Gas connection | 1/2" gas inlet | 1/2" gas inlet |
| Control | Control delays burner start until residual heat is transferred | Control delays burner start until residual heat is transferred |
| Fuel | Natural gas or propane | Natural gas or propane |
| Venting (chimney / sidewall) | 4" chimney / 3" sidewall | 4" chimney / 3" sidewall |
Published ratings: the Pennco FSB-4 is rated 112.5 MBH input, 95 MBH heating capacity and 84% AFUE; the Pennco FSB-5 is rated 150 MBH input, 127 MBH heating capacity and 84% AFUE. Pennco FSB-5 lists 37.5 MBH more input than Pennco FSB-4 (150 MBH against 112.5 MBH). Both list the same published AFUE of 84%.
Pennco FSB-5 lists 48 lb more shipping weight than Pennco FSB-4 (370 lb against 322 lb). The dimensions differs: the Pennco FSB-4 lists 17-1/2" × 29" × 23-1/4", while the Pennco FSB-5 lists 20-3/4" × 29" × 23-1/4".
Both records print the same AFUE (84%), domestic-hot-water arrangement (Heating-only boiler — domestic hot water comes from a separate indirect tank or water heater), venting (Chimney or sidewall vented) and water connections (1-1/4" supply and return tappings), per the cited sources.
Pennco
The Pennco FSB-4 is the mid-size FSB: 112.5 MBH input with 95 MBH heating capacity and a 82 MBH net water rating at 84% AFUE, vented through a 4" chimney or 3" sidewall connection.
Pennco
The Pennco FSB-5 is the second-largest FSB size: 150 MBH input with 127 MBH heating capacity and a 109 MBH net water rating at 84% AFUE, vented through a 4" chimney or 3" sidewall connection.
The Pennco FSB-5 lists 150 MBH, against 112.5 MBH on the Pennco FSB-4, per the cited documentation.
Both list the same AFUE of 84%.
It ships at 370 lb against 322 lb for the Pennco FSB-4, per the cited sources.
A consultation includes a heat-loss review so the size is right the first time.
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.