CGA-6 - 122,000 BTU Output Boiler, Spark Ignition - Series 3 (Natural Gas)

Weil-McLain CGA-6 Series 3 – High-Efficiency Gas Boiler for Demanding Hydronic Applications

The Weil-McLain CGA-6 Series 3 is a natural draft, gas-fired cast iron boiler engineered for residential and light commercial hydronic heating. With an input of 166,000 BTU/h and a DOE heating capacity of 141,000 BTU/h, it delivers consistent, high-output performance for systems requiring reliable, steady heat production. Designed with field-proven components and an AFUE rating of 84%, this unit meets modern efficiency standards while maintaining the robustness contractors expect from cast iron construction.

Performance and Design Highlights

• Cast Iron Heat Exchanger – Precision-machined for uniform heat distribution and extended lifecycle in hydronic systems.
• Integrated Control Module – Includes spark ignition, diagnostic LED indicators, and safety shutdown for streamlined troubleshooting and service.
• Low Water Cut-Off – Factory-integrated to prevent dry firing and protect the heat exchanger from premature failure.
• Vertical Flueways – Improve heat transfer and provide easy top-side access for brush-down maintenance.
• Stainless Steel Burners – Durable and corrosion-resistant, providing stable combustion and quiet operation.

Key Technical Specifications

• Model: CGA-6 Series 3
• Input: 166,000 BTU/h
• DOE Heating Capacity: 141,000 BTU/h
• Net AHRI Rating: 122,000 BTU/h
• AFUE: 84%
• Fuel: Natural Gas
• Vent Size: 6-inch
• Water Content: 3.3 gallons
• Weight: Approx. 325 lbs
• Ignition Type: Electronic Spark Ignition

System Integration Considerations

The CGA-6 is designed for integration into closed-loop hydronic systems with zone valves or circulators. It ships with a Taco 007 circulator, vent damper, pressure-temperature gauge, relief valve, and extended jacket insulation. System piping and venting must conform to local code requirements. Proper vent rise, gas supply sizing, and combustion air access are critical for safe and efficient operation.

Installation Guidance

Professional installation is recommended. Contractors should verify chimney draft, perform combustion analysis, and ensure flue pipe and gas line sizing align with site-specific demand. Wiring is simplified with a built-in junction box, and control terminals are easily accessible from the front panel. Cleaning access is provided via top-mounted flueway covers.

Professional Summary

For contractors looking for a dependable mid-size atmospheric gas boiler with cast iron durability and integrated safety controls, the CGA-6 Series 3 offers a proven solution. Its straightforward design supports both retrofit and new installations in systems requiring reliable output, manageable serviceability, and code-compliant efficiency.