Weil-McLain CGa-5
The CGa-5 is the first of the large-cabinet CGa Series 4 sizes, from the cast iron line discontinued in Canada in 2023: 133 MBH CSA input, 113 MBH DOE heating capacity and a 98 MBH net AHRI rating at 84% AFUE.
Key figures
- Max input
- 133 MBH
- Max CSA output
- 113 MBH
- AFUE
- 84 %
- Min input
- —
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Weil-McLain CGa-5 in practice
The CGa-5 raises the Series 4 line to 133 MBH CSA input with 113 MBH of DOE heating capacity and a 98 MBH net AHRI rating at 84% AFUE. Its 6" vent size reflects the larger cast iron sections of this natural-draft boiler, which the US page describes with stainless steel burners, built-in low water cut-off, quiet operation and easy top-access servicing.
The CGa is discontinued in Canada: Weil-McLain Canada's April 27, 2023 news release gave the non-condensing cast iron line a production cut-off of June 30, 2023 under federal efficiency standards, with parts support promised for at least 20+ years. The Canadian discontinued-page data (inputs 52-245 MBH, up to 84% AFUE, Cat. 1 B-vent, vertical vent only) belongs to the Series-3-era units sold before the cut-off; this Series 4 model set is the one Weil-McLain now sells in the US.
Best suited to
- Larger homes with chimney-vented loads in the 110-135 MBH band
- Contractors comparing Series 4 ratings with the Series-3-era CGa units in Canadian basements
- Cast iron boiler documentation for B-vent vertical-only installations
Applicability and support
- Model number
- CGa-5
- 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 Weil-McLain. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input, maximum | 133 MBH | CSA input per the US Series 4 product page. |
| Output | ||
| DOE heating capacity | 113 MBH | DOE heating capacity per the US Series 4 product page. |
| Net AHRI water rating | 98 MBH | Net AHRI water rating per the US Series 4 product page. |
| Efficiency | ||
| Efficiency (AFUE) | 84 % | 84% AFUE per the US Series 4 page; the CA discontinued page lists up to 84% for the Series-3-era Canadian units. |
| Venting and air | ||
| Venting | Category I, B-vent — vertical chimney venting only, natural draft | Per the CA discontinued page (Cat. 1 venting, B-Vent; vertical vent only, 50 psi relief option); the US Series 4 page lists a 6" vent size for the CGa-5. |
| Operating limits and other | ||
| Fuel | Natural gas or propane | Propane requires a conversion kit per the CA product page. |
Manuals
- CGa Series 4 Boiler Manual, 550-100-223/0425550-100-223/0425 · 2025-04
Alerts documented for this model
- CONFIRM CONFIGURATION
- CONFIG MISMATCH
- AUTO LIMIT OPEN
- MANUAL LIMIT OPEN
- FALSE FLAME
- IGNITION FAULT
- FLAME LOST
- BOILER OUT OPEN
- BOILER OUT SHORT
- HARDWARE FAULT 1
- HARDWARE FAULT 2
- HARDWARE FAULT 3
- HARDWARE FAULT 4
- HARDWARE FAULT 5
- HARDWARE FAULT 6
- HARDWARE FAULT 7
- HARDWARE FAULT 8
- CH VOLTAGE HIGH
- DHW VOLTAGE HIGH
- SPILL SWITCH
Frequently asked questions
What are the CGa-5's ratings?
133 MBH CSA input, 113 MBH DOE heating capacity, a 98 MBH net AHRI rating and 84% AFUE, with a 6" vent size per the US Series 4 product page.
Why does Boilers.ca document US Series 4 CGa models?
Weil-McLain Canada's discontinued page carries no per-model ratings for the Series-3-era Canadian units, so Boilers.ca records the current US Series 4 set documented by manual 550-100-223/0425 and flags the generation difference.
Can I still get parts for a Canadian CGa?
Weil-McLain Canada's phase-out notice states parts will be available for at least 20+ years from the 2023 production cut-off.
Questions about the Weil-McLain CGa-5?
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
- Weil-McLain Canada — CGa (discontinued) · accessed September 8, 2026
- Weil-McLain Canada — Residential boiler efficiency changes (Apr 27, 2023) · accessed September 8, 2026
- CGa Series 4 Boiler Manual 550-100-223/0425 · 550-100-223/0425 · accessed September 8, 2026
Facts checked September 8, 2026. Last updated September 8, 2026. Technical reviewer: not yet assigned.