DuraVent FasNSeal Stepped Increaser: a short step up where a tapered fitting won’t fit
The DuraVent FasNSeal Stepped Increaser is a stainless steel fitting that joins a smaller vent section to the next size up. It makes that change over just 6 inches, for places without enough room for a longer tapered fitting. It can also connect certain pool heaters and boilers to a vent larger than their outlet, where DuraVent specifies that pairing. FasNSeal is DuraVent’s stainless steel vent for high efficiency gas boilers, furnaces, and water heaters, built to carry pressurized exhaust and its acidic condensate outside.
Choose the 3 to 4 inch or 4 to 5 inch transition on this page. Other sizes are made to order. The vent is stainless steel inside and out, with welded seams. An experienced venting professional should handle the work, and DuraVent recommends a yearly check of the complete run by a qualified inspector. Need the double wall version? See the DuraVent FasNSeal W2 Stepped Increaser double wall fitting. The DuraVent FasNSeal Stepped Increaser ships free from My Cozy Outdoors with No Sales Tax (except WY) and the full manufacturer warranty.








Commercial projects may require custom parts and unique system designs. Duravent offers complete project assistance:








































