National Chimney M-Flex Chimney Liner | 6-Inch

The National Chimney M-FLEX 6-Inch Stainless Steel Chimney Liner provides superior durability and flexibility for relining existing chimneys or new construction, ensuring optimal venting performance.

Key Features:

• High-grade 316L stainless steel construction

• Flexible and easy to install

• UL 1777 Listed and tested for all fuel types

Product Features

Durable 316L Stainless Steel

Constructed from .006” thick, mill-certified 316L stainless steel, offering maximum strength and resistance to corrosion and creosote buildup.

Superior Flexibility

The corrugated, 7-ply interlocked and crimped construction provides flexibility, making it easy to navigate tight spaces within your chimney.

Gas and Watertight Design

The liner's unique construction creates a secure, watertight, and airtight seal, accommodating thermal expansion and contraction safely.

UL Listed for All Fuels

UL 1777, UL 64, and UL 441 listed, suitable for venting wood, pellet, coal, oil, gas, and corn-burning appliances safely and reliably.

Lifetime Transferable Warranty

Comes with a lifetime transferable warranty when professionally maintained, providing long-term peace of mind.

Product Specifications

Warranty

M-Flex™ Chimney Liner Limited Lifetime Warranty

National Chimney Supply, Inc. (N.C.S.) guarantees that the M-Flex chimney liners and components are free from defects in materials and manufacturer workmanship. This warranty also covers perforation caused by chimney fires or overfiring due to user operation, as well as corrosion resistance.

The warranty provides lifetime coverage for wood, wood pellet, gas, and oil-burning installations when used to vent UL-listed residential wood-burning stoves and fireplaces, wood pellet stoves, Category 1 residential gas and oil heating systems, Category 1 gas and oil water heaters, gas fireplaces, or gas logs. The warranty is valid for the lifetime of the original purchaser as long as they own the home where the M-Flex liner was originally installed. If the home is sold, the warranty transfers to the new homeowner. For M-Flex, coverage remains lifetime, while for M-Flex Lite, the warranty transfers for a period of 10 years from the installation date.

The warranty is subject to the following conditions. The liner and components must be installed according to the manufacturer’s written installation instructions. The liner must be used only for its intended purpose, which is the lining or relining of chimneys for residential appliances. Additionally, the liner must be inspected, maintained, and cleaned annually, starting one year after installation and continuing at intervals of no more than 12 months. These inspections must be performed by a nationally certified chimney sweep, an M-Flex installer, or another qualified chimney professional, who must complete the M-Flex Maintenance Record.

To maintain warranty coverage, certain requirements must be met throughout the warranty period. The chimney must have a cap to prevent debris and water intrusion. Corrosive chemical chimney cleaners must not be used, and plastic bristle flue cleaning brushes are recommended instead of metal bristle brushes. Burning prohibited materials will void the warranty. The following must not be burned in an appliance or fireplace connected to the M-Flex liner: driftwood, wood or pellets containing salt, pressure-treated lumber, plastic, or household trash. In the event of a chimney fire, the liner must be inspected by a nationally certified chimney sweep, an M-Flex installer, or another qualified chimney professional before reuse.

If you need to file a warranty claim, contact your M-Flex installer, who will provide National Chimney Supply (N.C.S.) with the necessary information. If N.C.S. requires a factory inspection of the defective part, they will cover the shipping costs for the material to be inspected. If the material is deemed defective, N.C.S. will cover the cost of replacement material and shipping. This warranty does not cover costs for removal or reinstallation of the liner, nor does it provide liability for special, incidental, or consequential damages arising from a defect or damage to the M-Flex liner.

This warranty gives you specific legal rights, and you may have additional rights that vary by state regarding the exclusion or limitation of incidental or consequential damages.