Weil-McLain EG-45
The EG-45 is the 150 MBH EG size: 127/124 MBH water/steam DOE heating capacity, 388 sq ft of steam coverage, 84%/82% AFUE and a 6" I.D. chimney — discontinued in Canada, current in the US.
Key figures
- Max input
- 150 MBH
- Max CSA output
- —
- AFUE
- —
- Min input
- —
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Weil-McLain EG-45 in practice
At 150 MBH CSA input the EG-45 produces 127 MBH of DOE water heating capacity and 124 MBH in steam, with net AHRI ratings of 110 MBH water and 93 MBH steam covering 388 sq ft. It is rated 84% AFUE in water and 82% in steam and ships at approximately 505 lb.
The boiler is atmospheric cast iron with Category I, B-vent venting, vertical only, using a draft hood, an automatic vent damper and a 6" I.D. chimney collar. The manual lists 3" supply and 2-1/2" return tappings, a 1/2" gas connection, a 3/4" relief tapping, 14.8 gal of water content and 9.8 gal to the steam waterline. The EG line is discontinued in Canada, where the CA page sits in the Discontinued menu, while the US continues it as Series 6 and Series 7.
Best suited to
- Larger residential or light-commercial steam loads near 150 MBH
- Chimney-vented replacements needing about 388 sq ft of steam
- Documenting a Canadian-discontinued EG unit
Applicability and support
- Model number
- EG-45
- Canadian availability
- historical
- Production status
- discontinued
- 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 Weil-McLain. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input, maximum | 150 MBH | CSA input per the US EG Series 6/7 spec tables and the EG Series 7 manual ratings table (Table 20). |
| Output | ||
| DOE heating capacity, water | 127 MBH | Water heating capacity per manual Table 20; matches the CA discontinued page's output figure. |
| DOE heating capacity, steam | 124 MBH | Steam heating capacity per manual Table 20. |
| Net AHRI rating, water | 110 MBH | Net AHRI water rating based on a 1.15 piping and pick-up allowance per the manual ratings notes. |
| Net AHRI rating, steam | 93 MBH | Net AHRI steam rating based on a 1.333 pick-up allowance per the manual ratings notes. |
| Net AHRI steam rating, area | 388 sq ft | Steam square-foot rating per manual Table 20; the CA discontinued page's published range ends at 750 sq ft, which does not match the EG-75's 733 sq ft. |
| Efficiency | ||
| AFUE, water | 84 % | 84.0% AFUE in water per manual Table 21 and the US spec tables. |
| AFUE, steam | 82 % | 82.0% AFUE in steam per manual Table 21 and the US spec tables. |
| Venting and air | ||
| Venting | Category I, B-vent — vertical vent only, natural draft with draft hood and automatic vent damper; 6" I.D. chimney x 20 ft | Per the US spec tables (chimney size) and the CA discontinued page (Cat. 1, B-vent, vertical vent only). |
| Physical and connections | ||
| Supply connection | 3" | Supply tapping O is 1 x 3" on every EG/PEG size per the Series 7 manual connections section. |
| Return connection | 2-1/2" | Return tapping P is 1 x 2-1/2" on every EG/PEG size per the Series 7 manual connections section. |
| Gas connection | 1/2" | Gas connection F is 1/2" on EG/PEG-30 through -55 per the Series 7 manual. |
| Relief valve | 3/4" tapping | Water boilers use a 3/4" tapping on the side with a 30 psi relief valve; steam boilers use a 15 psi relief valve on a top tapping per the Series 7 manual. |
| Weight | 505 lb | Approximate shipping weight per the US spec tables and manual Table 20. |
| Operating limits and other | ||
| Boiler water content | 14.8 gal | Water content per manual Table 20. |
| Steam-to-waterline content | 9.8 gal | Steam-to-waterline water content per manual Table 20. |
Manuals
- EG Series 7 Boiler Manual, 550-100-225/0425550-100-225/0425 · 2025-04
Alerts documented for this model
- CONFIRM CONFIGURATION
- CONFIG MISMATCH
- AUTO LIMIT
- MANUAL LIMIT
- 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
- POWER (flashes once per second)
- Flash code 2
- Flash code 5
- Flash code 6
- ALL LED'S FLASHING
- Solid LWCO LED
- POWER + TSTAT/CIRC
- POWER + DAMPER
- POWER + FLAME
- DAMPER
- LIMIT
- FLAME
- LWCO
Frequently asked questions
What are the EG-45's ratings?
150 MBH CSA input, 127 MBH DOE water heating capacity, 124 MBH steam, 110 MBH net AHRI water, 93 MBH net AHRI steam (388 sq ft), and 84% water / 82% steam AFUE per the US spec tables and manual.
How much steam can the EG-45 cover?
The manual's net AHRI steam rating is 93 MBH covering 388 sq ft at a 1.333 pick-up allowance.
What gas connection does the EG-45 use?
A 1/2" gas connection; the 3/4" size starts on the EG-65 and EG-75, per the EG Series 7 manual.
Questions about the Weil-McLain EG-45?
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.
Compare and explore
- Weil-McLain EG-40 vs EG-45Comparison
- Weil-McLain EG-45 vs EG-50Comparison
- Weil-McLain EG-30Same series
- Weil-McLain EG-35Same series
- Weil-McLain EG-40Same series
- Weil-McLain EG-50Same series
- Weil-McLain EG-55Same series
- Weil-McLain EG-65Same series
- Weil-McLain EG-75Same series
- EG / EG Steam series hub
- Buying guide
Sources and verification
- Weil-McLain Canada — EG / EG Steam (discontinued) · accessed September 9, 2026
- Weil-McLain — EG Series 7 Gas Boiler · accessed September 9, 2026
- EG Series 7 Boiler Manual 550-100-225/0425 · 550-100-225/0425 · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.