Weil‑McLain EG‑45 – 150 MBH Cast‑Iron Water Boiler, 84 % AFUE
The EG‑45 is a rugged, sectional cast‑iron boiler designed for hydronic (water) heating service. With a 150 MBH input and approximately 124 MBH net IBR rating for water systems, it delivers solid performance and up to 84% DOE AFUE efficiency. The unit also includes a knock‑down (disassembled) left‑end opening ready to accept an optional internal tankless hot‑water heater coil
boilersupplies.com
+12
afsupply.com
+12
afsupply.com
+12
.
???? Key Contractor-Level Features
Durable Cast‑Iron Construction
Sectional cast‑iron block rated for 50 PSIG, wrapped in an insulated jacket with a horizontal‑to‑vertical draft hood.
afsupply.com
+1
afsupply.com
+1
Fuel‑Saving Auto Vent Damper
Includes a built-in vent damper to reduce heat losses when not firing—standard on EG‑45.
boilersupplies.com
+12
afsupply.com
+12
afsupply.com
+12
Intermittent Electronic Ignition
Stainless burners with intermittent ignition and a combination gas valve ensure reliable starts and clean combustion.
homeperfect.com
+11
afsupply.com
+11
plimptonhills.com
+11
Service-Friendly Access
Front-access control panel, plug-in wiring harness, rollout thermal fuse, and spill switch make maintenance and diagnostics efficient
weil-mclain.com
+6
afsupply.com
+6
plimptonhills.com
+6
.
Collision of Water/Steam Capabilities
Primed for steam or water applications. Water version features air separator, 30 PSI relief valve, combo gauge, high-limit control, and low-water cutoff
boilersupplies.com
+4
plimptonhills.com
+4
weil-mclain.com
+4
oswaldsupply.com
+3
afsupply.com
+3
afsupply.com
+3
.
Tankless Hot-Water Coil Ready
Knock-down left-end with opening for internal tankless coil—ideal for indirect domestic hot water applications. Must be ordered with coil kit.
reddit.com
+3
afsupply.com
+3
weil-mclain.com
+3
???? Contractor’s Spec Table
Specification Details
Input Capacity 150 MBH
Net Output (Water, MBH) ~124 MBH
AFUE 84%
Pressure Rating 50 PSIG
Vent Size 6″ ID chimney x 20′ minimum
Ignition & Controls Intermittent × electronic, plug-in module
Jacket & Draft Hood Insulated steel jacket & vertical hood
Service Weight ~505 lb
Warranty Water: 20 yr exchanger &, 2 yr parts
???? Installation Notes
Vent Requirements: Requires 6″ chimney; automatic damper aids efficiency.
weil-mclain.com
+1
weil-mclain.com
+1
boilersupplies.com
+5
afsupply.com
+5
plimptonhills.com
+5
Ignition Protocol: Must be used with natural gas; no propane conversion option.
ussupply.com
+13
afsupply.com
+13
weil-mclain.com
+13
Tankless Coil Access: Coil opening installed at factory; coil kit required separately.
ecomfort.com
+11
ussupply.com
+11
homeperfect.com
+11
✅ Summary for Contractors
The EG‑45 cleanly blends time-tested cast‑iron longevity with modern efficiency and service ease. Automatic venting and electronic ignition reduce fuel waste, while plug‑in controls, coil readiness, and flexible fuel options make it adaptable on-site. Robust 150 MBH capacity suits mid‑to‑large residential or light commercial jobs, and the sectional design fits through 30″ openings when assembled on-site.