Application: Single wall insulated Class A chimney pipe or chimney liner. This is the premier chimney cap for solving common, wind-related chimney draft problems. Wind-induced downdraft can cause smoke to enter the living space when: hills, mountains, tall trees, and/or tall buildings are in the vicinity. Vacu-Stack also functions as a conventional chimney cap by protecting the chimney from rain, snow, debris, and animals. The optional stainless steel 1" mesh screens, used as bird guards, will never rust and are available for either style of Vacu-Stack caps. The screen will assist against debris and animals from entering the chimney and will help contain sparks. See how the Vacu-Stack Chimney Cap works. Adapt your Vacu-Stack chimney cap to any standard masonry flue using this adapter. Sizing: Diameter A (Inside Flue Dimension) Diameter C 6" 14" 7" 15" 8" 18" 9" 20" 10" 21" 11" 23" 12" 24" The 8 in. x 12 in. Oval Vacu-Stack extension measures 5 7/8" W x 9 7/8" L. The plate measures 10" W x 14" L. Installation Instructions: Vacu-Stack Mesh Screen Installation Instructions Step 1: Fitting the Vacu-Stack inside the flue. Vacu-Stack chimney caps fit inside round metal and masonry flues. Press the pipe end of the Vacu-Stack into the flue until fit is snug. Step 2: Applying a Watertight Seal. Apply a thin layer of silicone caulking to seal joint between Vacu-Stack and top of chimney. The chimney silicone is an optional add-on for this product. If you are installing on rectangle or square flues, please visit the masonry adapter page.
