4" x 25' Aluminum Liner Kit

Details

Model: 2GACKIT0425
Manufacturer: Z-Flex
Series: Z-Flex Aluminum Gas Venting System
Part Number: 72978
Description: Aluminum Chimney Liner Kit, 4 in. Diameter x 25 ft. Length, for Category I Natural Draft Gas Appliances.

Product Overview

The Z-Flex 2GACKIT0425 Aluminum Gas Liner Kit is a UL-listed flexible venting system designed for Category I natural draft gas-fired appliances and gas fireplaces. Constructed from high-grade aluminum, the liner provides a durable, corrosion-resistant flue for venting combustion gases through existing masonry chimneys. The 4-inch diameter and 25-foot length configuration supports standard gas heating appliances operating under negative pressure conditions. This system is engineered for retrofit and new installations requiring reliable draft control and compliance with NFPA 54 (National Fuel Gas Code) for natural draft applications.

Technical Specifications

• Manufacturer Part Number: 2GACKIT0425
• Alternate Part Number: 72978
• System Type: Flexible Aluminum Chimney Liner Kit
• Diameter: 4 inches (nominal)
• Length: 25 feet
• Material: Corrugated aluminum alloy
• Listing/Certification: UL Listed for Category I natural draft gas appliances
• Application: Natural draft gas-fired furnaces, boilers, water heaters, and gas fireplaces
• Category Compatibility: Category I only (non-condensing, negative pressure)
• Excluded Categories: Not suitable for Category II, III, or IV appliances, or for systems producing condensation or corrosive byproducts
• Operating Pressure: Negative pressure venting system only
• Temperature Rating: Standard flue gas temperatures for atmospheric gas appliances
• Included Components: 25 ft aluminum liner, top termination, appliance connector, fasteners, and support components
• Installation Type: Flexible liner for retrofit through existing chimney or vent structure
• Code Compliance: Conforms to NFPA 54 and ANSI Z223.1 for gas venting systems
• Environment: Indoor use, within vented chimney enclosures

Installation Notes

• Use only with Category I natural draft gas-fired appliances.
• Inspect chimney condition and clear obstructions prior to liner installation.
• Maintain manufacturer-recommended clearances and sealing practices.
• Do not use in positive pressure or condensing vent applications.
• Secure terminations and joints per Z-Flex installation instructions to ensure airtight connections.

Summary

The Z-Flex 2GACKIT0425 Aluminum Gas Liner Kit is a UL-listed venting solution engineered for Category I natural draft gas heating systems. Featuring a 4-inch flexible aluminum liner with a 25-foot reach, it provides reliable flue gas containment and consistent draft performance in retrofit and new chimney installations. The system delivers code-compliant operation and long-term durability for professional mechanical and HVAC installations.