Gas-Fired Water Boiler, 90K BTU, 84% AFUE, Series 3

Williamson GWI-090-N-T-S3-W – 95,000 BTU Direct Vent Gas-Fired Water Boiler

The Williamson GWI-090-N-T-S3-W is a gas-fired, cast iron boiler engineered for direct vent residential hot water heating systems. Designed for long-term reliability and efficiency, this model delivers 95,000 BTU input with an 84% AFUE rating and is suitable for standard baseboard, radiator, or radiant panel installations.

Product Highlights

• Direct Vent Configuration: Sealed combustion system draws air from outside and exhausts directly outdoors, eliminating the need for a chimney and improving safety in confined mechanical spaces.
• Cast Iron Heat Exchanger: Precision-machined sections provide thermal stability and long service life in hydronic heating applications.
• Electronic Ignition: Intermittent pilot ignition system enhances energy efficiency and simplifies annual maintenance.
• Integrated Controls: Factory-installed combination aquastat and circulator relay for quick start-up and wiring convenience.
• Vent Termination Kit: Designed for through-wall installations using concentric vent piping; supports multiple layout configurations.

Technical Specifications

• Model: GWI-090-N-T-S3-W
• Input: 95,000 BTU/hr
• DOE Heating Capacity: 82,000 BTU/hr
• Net I=B=R Rating: 71,000 BTU/hr
• AFUE: 84%
• Fuel: Natural Gas
• Vent Type: Horizontal/Direct Vent
• Burner: Atmospheric
• Construction: Cast iron heat exchanger, steel jacket

Installation Requirements

Installation must be performed in accordance with ANSI Z223.1/NFPA 54 and local code requirements. Direct vent models require concentric or two-pipe sealed venting systems with specific clearances to combustibles and wall penetrations. This boiler ships with a factory-wired circulator and service switch, reducing onsite setup time.

Professional Considerations

• Flue Gas Handling: Venting components must meet UL 1738 (Category III) standards; do not substitute materials.
• Circulator Sizing: Ensure compatibility with system flow rates and head loss; review pump curve against zoning strategy.
• System Water Quality: Follow manufacturer guidance on fill water treatment and periodic testing to prevent section scaling or corrosion.

Contractor-Focused Features

• Access Panels: Quick-removal jacket sections allow full access to the burner compartment and control wiring terminals.
• Electrical Connections: Simplified terminal block setup supports easy integration with thermostats, zone valves, and external controls.
• Space-Efficient Design: Compact footprint and zero-clearance sides for tight mechanical rooms or closet installations.

Summary

The Williamson GWI-090-N-T-S3-W is a robust, cast iron gas boiler with sealed combustion, making it ideal for new construction and retrofit installations where chimney venting is not practical. Backed by a durable design and service-friendly layout, it offers dependable performance across residential hydronic applications.