Natural GAS Boiler, 38 MBH, 87% AFUE, Series 3

Williamson GWA-038-N-T-S3-W – Atmospheric Gas Boiler, Series 3

The Williamson GWA-038-N-T-S3-W is a cast iron, atmospheric vent gas boiler engineered for residential hot water applications. Rated at 38,000 BTU input and delivering 33,000 BTU DOE heating capacity, it operates with an 87% AFUE efficiency, meeting federal energy standards for non-condensing gas-fired boilers.

This model is part of the Series 3 line, known for reliable field performance and long-term service life. It features factory-installed flue baffles and an automatic vent damper for improved seasonal efficiency, and its sectional cast iron heat exchanger ensures heat retention and durability under sustained operation.

Technical Specifications

• Model: GWA-038-N-T-S3-W
• Input: 38,000 BTU/hr
• Heating Capacity: 33,000 BTU/hr (DOE)
• Net I=B=R Rating: 29,000 BTU/hr
• AFUE: 87%
• Fuel: Natural Gas
• Ignition: Electronic intermittent pilot
• Vent Type: Atmospheric, 4" flue outlet
• Burner: Stainless steel atmospheric burners
• Heat Exchanger: Cast iron, sectional

System Integration & Design Notes

• Equipped with factory-wired circulator and integral control module
• Automatic vent damper included for post-purge energy savings
• Built-in flue baffles increase heat transfer surface area
• Combustion chamber access via front-panel design for serviceability
• Pressure relief valve and temperature/pressure gauge shipped standard

Installation Requirements

This unit is intended for installation in Category I natural draft vent systems using single-wall or Type B gas vent. Sizing must follow Manual J heat load calculations and local code compliance. Minimum clearance and combustion air specifications must be met. Connection to an indirect water heater or multiple zoning system is supported with standard circulator relay wiring.

Professional installation is strongly recommended due to code-specific venting requirements and proper gas pressure regulation. Contractors should perform combustion analysis during startup and confirm water quality meets boiler manufacturer specifications.

Key Applications

• Single-family homes with fin-tube baseboard or cast iron radiator systems
• Low-pressure closed-loop hydronic systems up to 50 PSIG working pressure
• Zone-valve or pump-controlled systems with external relay control

Summary

The Williamson GWA-038-N-T-S3-W boiler offers efficient and reliable hydronic heating in a compact cast iron platform, with an 87% AFUE, corrosion-resistant components, and proven atmospheric burner performance. It is well-suited for new installations and system replacements where dependable hot water heat delivery and simple operation are priorities.