CGA-4 - 73,000 BTU Output Boiler, Spark Ignition - Series 3 (Natural Gas)

Weil-McLain CGA-4 – 84% AFUE Natural Draft Gas Boiler, 73,000 BTU

The Weil-McLain CGA-4 is a cast iron, gas-fired boiler designed for residential hydronic heating systems. With a DOE heating capacity of 73,000 BTU/h and an 84% AFUE rating, this unit is engineered for consistent performance and energy-efficient operation in gravity or forced hot water systems. Suitable for baseboard, panel radiators, or radiant loops, the CGA-4 is a proven solution for small to mid-sized zones requiring dependable heat output and long service life.

Professional-Grade Features

• Natural Gas Input: 90,000 BTU/h
• DOE Heating Capacity: 73,000 BTU/h
• Net I=B=R Rating: 63,000 BTU/h
• Annual Fuel Utilization Efficiency: 84%
• Heat Exchanger: Cast iron sectional design for durability and thermal mass
• Burner System: Orificed stainless steel burners for optimal flame retention and quiet ignition
• Combustion Type: Atmospheric, non-condensing

System Protection and Controls

• Integral Low Water Cutoff (LWCO): Factory-installed for system safety
• Control Module: Integrated electronic control with intermittent ignition
• Draft Hood: Included for vertical Category I venting with B-vent or lined masonry chimney
• Flue Outlet: 5-inch diameter

Installation Considerations

This unit is designed for floor-mounted installation in dry, well-ventilated mechanical spaces. Proper gas line sizing, combustion air supply, and venting are required for safe and code-compliant operation. Clearance, piping layout, and zone control strategies should align with system-specific design requirements. Professional installation by a licensed contractor is required to ensure warranty validity and regulatory compliance.

Physical Dimensions

• Width: 14-7/8"
• Depth: 26-3/4"
• Height: 30-1/2"
• Approximate Shipping Weight: 285 lbs

Application Scope

Ideal for retrofits or new installations in single-family residences, the CGA-4 is suitable for closed-loop hydronic systems utilizing baseboards, radiators, or radiant floor distribution. Not compatible with direct vent, condensing, or sealed combustion setups.