FAQs

Yes. The distribution box includes flow restrictors that allow precise balancing of airflow for each room. This gives homeowners more comfort control, ensures consistent air delivery to every space, and eliminates the need for costly on-site balancing or commissioning.

No. Because Air Excellent is pre-engineered and pressure-calculated, it eliminates the need for field commissioning in most installations. This saves installers time, labor costs, and callbacks, while guaranteeing that the system performs as designed right from installation.

Yes. Centrotherm provides a free design service that calculates airflow restrictions, ensures balanced ventilation, and generates a complete Bill of Materials. This gives installers confidence that every system is engineered correctly before installation, saving time and preventing costly mistakes.

The system uses snap-fit, gasket-sealed connections that make it completely mechanical and airtight. This eliminates the need for duct tape, sealant, or screws, common leakage points in traditional ducting. Airtight ducts mean better energy efficiency, lower operating costs, and quieter system performance.

Yes. Air Excellent is compact and designed to fit within 2x4 or 2x6 stud walls, ceilings, and floors, making it ideal for both new builds and retrofit projects. Its flexibility means minimal demolition in renovations, while the sleek design integrates easily with modern construction methods.

• Energy Efficiency: Airtight ducts prevent energy losses.
• Health & Safety: Anti-microbial, anti-static, and VOC-free materials improve indoor air quality.
• Durability: Rust-proof, impact-resistant, and long-lasting materials reduce maintenance.
• Flexibility: Semi-rigid ducts allow easy installation in walls, floors, or ceilings with fewer fittings.
• Noise Reduction: The smooth interior reduces air resistance and creates a quieter system.
• Sustainability: Materials are recyclable and eco-friendly.

Yes. Across Canada, all plastic venting systems for gas appliances must be certified to ULC S636, as mandated by Clause 8.9.6 of the CSA B149.1 Natural Gas and Propane Installation Code. This national code is adopted in every province and territory, sometimes with local amendments, but the ULC S636 requirement applies everywhere. Provincial safety authorities (such as TSSA in Ontario, Technical Safety BC, and the Régie du bâtiment du Québec) enforce compliance.

While polypropylene may carry a slight material premium, installers typically save significant time, often up to 70% on labor, because ULC S636 polypropylene vent systems are faster and easier to install. The overall installed cost is often lower compared to alternative venting materials, particularly when factoring in long-term reliability and fewer call-backs.

InnoFlue® polypropylene Special Gas Vent Systems, tested and listed to ULC S636, have been available in Canada since 2009. Polypropylene venting has been widely used in Europe for over 25 years, establishing a proven track record of safety and performance.

ULC S636 certification ensures that:

• The entire venting system (pipe, fittings, and seals) is tested and listed as a complete assembly.
• The system meets strict performance requirements for temperature, pressure, and leakage.
• Only factory-listed components may be used; field-fabricated or mixed-material venting is not permitted.
• The vent system is safe and compliant when installed according to the listing and manufacturer’s instructions.

InnoFlue® ULC S636 venting systems are available from plumbing and HVAC wholesalers across Canada, making them easy to source for contractors and distributors nationwide.

Both standards certify venting systems for use with condensing appliances, but UL-1738 is more stringent than ULC S636. Notable differences include:

• Pressure Testing: UL-1738 tests at 250% of rated operating pressure. ULC S636 has no pressure test requirement.
• Leakage Testing: ULC S636 allows leakage of 0.3 L/h @ 100 Pa, which is at a pressure 24% lower than UL-1738 testing.
• Puncture Test: UL-1738 requires resistance to a steel plunger drop test. ULC S636 does not.
• Low Temperature Handling: UL-1738 requires a -20°C drop test with no cracks or failures. ULC S636 has no cold weather test.
• UV Testing: UL-1738 includes UV and water exposure conditioning before testing. ULC S636 has no UV test.
• High Temperature Testing: UL-1738 requires testing at 38.8°C (70°F) above rated temperature. ULC S636 does not.

InnoFlue® is approved for gas-fired Category II and IV appliances and is suitable for vertical or horizontal venting in new or retrofit installations, including chimneys, chases, and through-wall terminations. InnoFlue® Polypropylene also meets ULC-S636 code.

Connector Rings are required for an installation of 2″ through 5″ diameter InnoFlue® to be UL-1738 and ULC-S636 compliant. Centrotherm strongly recommends the use of Connector Rings on all installations. Diameters 6″ and larger do not require the use of Connector Rings.

InnoFlue® Polypropylene Special Gas Vent Systems can be field cut to length using a hacksaw and miter box or equivalent. InnoFlue® must be cut on the male end of the pipe, preserving the socketed (female) end. After making a cut, the end can be beveled at the contractor’s discretion. The end must be deburred using a standard deburring tool or sand paper.

Yes, the exterior of InnoFlue® can be painted. Please follow the surface preparation specified by the paint manufacturer.

Yes. For rooftop terminations, follow flashing and sealing instructions. Vertical terminations over 59” above the roof line must be supported with guy wires or braces.

Not directly. For underground applications, InnoFlue® must be installed inside a larger diameter, direct-bury-rated pipe. The vent must be pitched, supported, and allowed to expand/contract inside the sleeve.

Yes, InnoFlue® Flex can be field cut, but only in the rigid sections and when connecting to the female end of Single Wall.

When venting combustion gas, InnoFlue® Flex cannot be installed horizontally. The installation of InnoFlue® Flex in a horizontal configuration allows for the pooling of condensate. This can create sagging in the vent system leading to the creation of back pressure. Back pressure can result in a forced shut down of the heating appliance. InnoFlue® Flex and BlitzFlex® can be installed horizontally when used as an air intake.

InnoFlue® Flex can be installed in a shared chimney, assuming the flues are separated, if the ambient air temperature does not exceed 300°F (149°C).

InnoFlue® Flex should not be installed in a sheet rock wall.

InnoFlue® Polypropylene Special Gas Vent Systems can be installed in chases with offsets that do not exceed 45°. Chases can have multiple offsets.

No, InnoFlue® Flex is ULC-S636 listed exclusively for use as a combustion gas vent system inside of a chase.

The InnoFlue® Concentric vent kit must always be installed according to Centrotherm’s official installation instructions to ensure safety, compliance, and system performance.

The concentric vent system can be installed in a variety of chases, including masonry, B-vent, and sheet rock chases, offering flexibility for different construction types.

InnoFlue® Concentric vent kit combines exhaust gas venting and combustion air intake into a single concentric vent system. This design allows for a cleaner, more aesthetically pleasing installation, reduces the number of roof or wall penetrations, and helps save on labor and installation time.

A concentric vent is a type of venting system that incorporates both exhaust and intake air in one pipe-within-a-pipe design. The InnoFlue® Concentric vent kit features a durable metal outer with a polypropylene inner. Combustion gas is drawn through the space between the two pipes, while exhaust gases are safely expelled through the polypropylene inner pipe.

The InnoFlue® Concentric vent system is engineered to withstand flue gas temperatures up to 230°F (110°C).

InnoFlue® Concentric vent kits are approved for use with gas-fired Category II and Category IV appliances, making them versatile for residential and commercial applications.