Natural Gas Water Atmospheric Hot Water Boiler PAK Electronic133MBHIP Series 3 Gas Water Atmospheric Hot Water Boiler

Williamson GWA-133-N-T-S3-W – 133,000 BTU Natural Gas Atmospheric Boiler, Series 3

The Williamson GWA-133-N-T-S3-W is a cast iron, gas-fired water boiler engineered for reliable performance and consistent heat delivery in residential hydronic systems. With an input of 133,000 BTU/h and an 84% AFUE efficiency rating, this Series 3 model is well-suited for mid-sized homes requiring efficient baseboard or radiator heating.

This model features a natural draft design and spark ignition system for consistent start-up and operation. Factory-assembled components such as the vent damper, circulator, and controls streamline installation for professionals. It’s configured for use with natural gas and includes provisions for system safety and service accessibility.

Key Features

• Cast Iron Heat Exchanger: Provides long-term thermal performance and structural integrity under varying load conditions.
• Electronic Spark Ignition: Improves energy savings and eliminates the need for a standing pilot flame.
• Integrated Low Water Cutoff: Factory-installed for safety, preventing damage during low water conditions.
• Factory-Wired Vent Damper: Increases seasonal efficiency by reducing standby losses.
• Compact Cabinet: Heavy-gauge steel jacket with insulation reduces heat loss and noise during operation.

Technical Specifications

• Model: GWA-133-N-T-S3-W
• BTU Input: 133,000 BTU/h
• Heating Capacity (DOE): 116,000 BTU/h
• Net AHRI Rating: 101,000 BTU/h
• AFUE: 84%
• Fuel: Natural Gas
• Vent Size: 5-inch
• Water Content: 4.0 gallons
• Circulator: Included (Taco 007 or equivalent)

Installation Considerations

The GWA-133 is designed for ease of installation in retrofit or new construction applications. Supply and return tappings are top-mounted for flexibility in piping layout. The boiler is suitable for use with standard B-venting systems and should be installed by a licensed HVAC or plumbing contractor to ensure code compliance and proper system performance.

Contractor Applications

• Zone valve or multi-circulator hydronic systems
• Single-family residences with medium heating loads
• Natural draft systems where sealed combustion is not required

Additional Notes

• Service Access: Front-access panel provides straightforward access to controls and ignition components.
• Safety: Factory-installed relief valve and control wiring ensure safe operation and faster installation time.
• Efficiency: Equipped with flue baffles and an automatic vent damper to maintain seasonal efficiency.