DuraVent Answers Frequently Asked Questions About FasNSeal

Date: Apr 05, 2017

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Frequently Asked Questions

Can you switch between single wall, double wall and flex?
Yes, FasNSeal is a complete venting systems made up of single wall (FNS), double wall (W2) and FNS Flex. There are adapters to transition between the three components of the venting system.

Since the FasNSeal FNS and FasNSeal W2 are rigid, are they self supporting?
No, non-combustible hanger straps and wall brackets are needed for horizontal and vertical applications. On a horizontal run, hangar straps are required a minimum of every 6 ft. Wall Brackets are required after every transition from horizontal to a vertical run of over 10 ft., a minimum of every 12 ft. of vertical run, and after any offset in the vertical run.

Is FasNSeal acceptable for my application?
Refer to the appliance manufacturer’s instructions which will either call out the required vent or the listing standard that covers the appliance and venting.

Are power tools needed to tighten the clamp?
No, per our installation instructions: “Tighten the locking band with a nut driver until snug plus 1/4 turn.”
Tip: Since all the clamps are positioned 45° from the weld, if you line up all the welds, the clamps will line up, speeding up your installation!

Can the pipe be cut?
When the use of the FasNSeal Adjustable Vent Length is not an option, field cutting of single wall FNS is allowed. Detailed instructions of cutting single wall FNS can be found on page 7 of the FasNSeal installation instructions. Note: Adjustable vent lengths are a specially designed, unique part; cutting off the male end of a vent length will not give you an instant adjustable vent length!

Can lubricant be applied to the gasket during installation?
Either soapy water or a silicone based lubricant can be applied to the gasket to aid in the joint connection.
Warning: Never use Petroleum based lubricants.

How is slope achieved in the run?
There are several parts that will give you the minimum 1/4" per foot pitch. FasNSeal has 2° Adjustable Vent Length, 88° elbows and regular Adjustable Vent lengths as ways to build in slope.

Are drains required in the vent system?
Yes, If the appliance is a Category II or Category IV heating appliance. In some cases, multiple drains may be required. Follow local regulations, the appliance manufacturers instruction and the FasNSeal installation instruction for drain frequency and placement.

Can FasNSeal be used with other vent systems?
No, per the installation instructions: “Different manufactures have different joint systems and adhesive requirements. Do not mix pipe, fittings, or joining methods from different manufacturers.” PolyPro® can be used with FasNSeal since they are both UL636 listed and from the same manufacturer, see page 6 of the PolyPro installation instructions for more information.

Can I use screws in addition to the built-in clamp to attach the vent?
No, FasNSeal is a positive pressure system designed to drain and manage condensate. Some references from the installation instructions on this subject are: “Do not puncture the vent system!” and “Do not drill through or penetrate any part of the vent system.”

Is the FasNSeal vent system directional?
Yes, since FasNSeal is a special gas vent system designed to handle condensate, proper orientation of the vent is required. Flow arrows on the part labels and FasNSeal Flex indicate the direction of exhaust flow.  

What is the bead on the male end for?
The bead on the male end of the venting serves both as a visual guide as well as physical stop to show when the gasket is fully engaged. Refer to the Joint Connection section of the FasNSeal installation instructions beginning on page 8 for more details.

Are the elbows adjustable?
No, the elbows are welded to maintain the seal against air and gas leakage.


For current pricing and availability, please call customer service at (800) 835-4429.