Selkirk 104308 Round Vent Increaser 4 to 8 Inches

Product Description

The SELKIRK 104308 is a 4-inch to 8-inch round vent increaser fitting designed for use in Type B-style gas appliance venting systems. Constructed from 26-gauge galvanized steel, this increaser transitions vent pipe from a 4-inch inside diameter outlet to an 8-inch diameter line, allowing installers to step up vent size where system design or code requirements demand it. The fitting is UL Listed and manufactured in the USA. It is part of the RV line of round vent pipe and fittings, which is engineered for residential, light commercial, and industrial gas venting installations.

This increaser is used where a gas appliance vent connector must transition to a larger common vent or main vent stack. Typical applications include residential furnaces, water heaters, and boilers vented through single-wall or approved Type B round vent systems. The fitting is suited for light commercial and industrial settings as well. Installers working on multi-appliance venting manifolds will find this increaser appropriate for combining smaller individual appliance outlets into a larger common vent riser.

Key Features

• Transitions from 4-inch inside diameter to 8-inch vent pipe
• 26-gauge galvanized steel construction for corrosion resistance in venting environments
• UL Listed for use on approved gas appliances
• Manufactured in the USA
• Part of the SELKIRK RV line, rated for residential, light commercial, and industrial gas venting

Compatibility

Designed for use with the SELKIRK RV line of round vent pipe and fittings on approved gas appliances in residential, light commercial, and industrial venting applications.

Installation Notes

Installation should be performed by a licensed HVAC technician or plumber familiar with local gas venting codes, including applicable requirements of the International Fuel Gas Code. Always shut off the gas supply and allow appliances to cool before servicing vent connections. Ensure all joints are secured per manufacturer and code requirements, and verify that the completed vent system meets clearance and termination requirements before returning the appliance to service.

Technical Specifications

• Inside Diameter (Inlet): 4 inches
• Outside Diameter (Outlet): 8.5 inches
• Height: 3 inches
• Length: 8.5 inches
• Gauge: 26 GA
• Material: Galvanized Steel
• Weight: 0.575 pounds
• Certifications: UL Listed
• Prop 65: No
• Country of Origin: USA

Standard Information

• Brand: SELKIRK
• Manufacturer Part Number: 104308