DuraVent FasNSeal Stepped Reducer: a short size change for tight spots
The DuraVent FasNSeal Stepped Reducer is a short stainless steel fitting that connects a larger vent pipe to a smaller one. It drops the run by one size in a 6 inch section, making room for a size change where space is tight. 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 either 4 inch down to 3 inch or 5 inch down to 4 inch on this page. Other size combinations can be made to order.
A gasket and a built-in locking band sit at the fitting’s wider end to seal and hold the connection. Before ordering for a tight spot, remember that the vent still needs open space around it. Single wall FasNSeal must stay clear of wood and other materials that can burn. The space needed depends on the appliance’s exhaust temperature, and it must stay free of insulation. Need the double wall version? See the DuraVent FasNSeal W2 Stepped Reducer double wall fitting. The DuraVent FasNSeal Stepped Reducer 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:








































