Duravent 0304INC B-vent Increaser 3x4 Inches Double Wall

Product Description

The DURAVENT 0304INC is a double-wall B-vent increaser fitting designed to transition vent diameter from 3 inches to 4 inches within Category I gas appliance venting systems. Double-wall construction maintains required clearances to combustibles as specified by venting codes. The fitting connects between existing vent sections and allows installers to step up vent size where system design or appliance requirements call for a larger diameter run. Licensed HVAC technicians and gas fitters are the primary installers of this type of fitting.

This increaser is used in residential and light-commercial Category I natural draft gas appliance venting applications, including furnaces, boilers, and water heaters that require B-vent systems. It is installed at the point in the vent run where the diameter must increase from 3 inches to 4 inches, typically when transitioning from the appliance collar to a larger trunk line or when combining multiple appliance vents into a common vent.

Key Features

• Transitions vent diameter from 3 inches to 4 inches in a single fitting
• Double-wall construction maintains clearances to combustibles per B-vent system requirements
• Designed for Category I gas appliance venting systems
• Installs between standard B-vent sections for a secure, code-compatible connection
• Compatible with natural draft gas appliance venting configurations

Compatibility

Designed as an OEM-style replacement and new-installation fitting for double-wall B-vent systems requiring a 3-inch to 4-inch diameter increase in Category I gas appliance venting applications.

Installation Notes

Installation should be performed by a licensed HVAC technician or gas fitter in accordance with the International Fuel Gas Code (IFGC) and the appliance manufacturer's venting instructions. Shut off the gas supply and allow the appliance to cool completely before servicing any vent components. Ensure all vent joints are properly assembled and secured before returning the system to operation. Follow local authority having jurisdiction (AHJ) requirements for inspection and clearance.

Technical Specifications

• Inlet Diameter: 3 inches
• Outlet Diameter: 4 inches
• Construction: Double Wall
• Vent Type: B-Vent (Category I)

Standard Information

• Brand: DURAVENT
• Manufacturer Part Number: 0304INC