The Weil-McLain CGi™ Series 5 (Model 381-359-364) is a premium cast-iron, gas-fired hot-water boiler engineered for long-lasting comfort and efficiency. Designed for both residential and light commercial installations, this unit offers induced-draft performance, an 84% AFUE efficiency rating, and a durable cast-iron heat exchanger that ensures reliable operation for decades.

This CGi model includes Unity-CI text-based controls, a built-in low water cutoff, and a fully insulated jacket for improved thermal performance. With flexible venting, quiet operation, and proven reliability from Weil-McLain — North America’s most trusted boiler manufacturer — this system is an excellent choice for hydronic heating systems.

Key Features

• 84% AFUE Efficiency for dependable heating performance.

• Unity-CI electronic control with digital text display for simple setup & diagnostics.

• Induced-draft design — improves venting reliability and system stability.

• Integrated low-water cutoff system for added safety.

• Heavy-duty cast-iron heat exchanger designed for long service life.

• Flexible venting: natural draft or direct exhaust options.

• Compatible with ECO-HP heat pump systems (Weil-McLain hybrid-ready).

• Quiet operation with stainless-steel burners.

• Tested for 50 PSI working pressure (CSA certified).

• Made in the USA heat exchanger.

📐 Specifications (Model 381359364 – CGi Series 5)