GE 39-40425 Installation Instructions Manual

EQUIVALENT NUMBER EQUIVALENTDUCT PIECES LENGTH x USED = LENGTHRectangular-to-Round 5 Ft. x ( ) = Ft.Transition Adaptor*Wall Cap 40 Ft. x ( ) = Ft.90° Elbow 10 Ft. x ( ) = Ft.45° Elbow 5 Ft. x ( ) = Ft.90° Elbow 25 Ft. x ( ) = Ft.45° Elbow 5 Ft. x ( ) = Ft.Roof Cap 24 Ft. x ( ) = Ft.Straight Duct 6″ Round or 1 Ft. x ( ) = Ft.31⁄4″ x 10″ RectangularTotal Ductwork = Ft.Equivalent lengths of duct pieces are based on actual testsand reflect requirements for good venting performance withany vent hood.* IMPORTANT: If a rectangular-to-round transitionadaptor is used, the bottom corners of the damperwill have to be cut to fit, using the tin snips, in orderto allow free movement of the damper.NOTE: If you need to install ducts, note that the totalduct length of 3 1⁄4″ x 10″ rectangular or 6″ diameterround duct should not exceed 140 equivalent feet.Outside ventilation requires a HOOD EXHAUST DUCT.Read the following carefully.NOTE: It is important that venting be installed usingthe most direct route and with as few elbows as possible.This ensures clear venting of exhaust and helps preventblockages. Also, make sure dampers swing freely andnothing is blocking the ducts.Exhaust connection:The hood exhaust has been designed to mate witha standard 3 1⁄4″ x 10″ rectangular duct.If a round duct is required, a rectangular-to-roundtransition adaptor must be used. Do not use less thana 6″ diameter duct.Maximum duct length:For satisfactory air movement, the total duct length of31⁄4″ x 10″ rectangular or 6″ diameter round duct shouldnot exceed 140 equivalent feet.Elbows, transitions, wall and roof caps,etc., present additional resistance to airflow and areequivalent to a section of straight duct which is longerthan their actual physical size. When calculating the totalduct length, add the equivalent lengths of all transitionsand adaptors plus the length of all straight duct sections.The chart below shows you how to calculate totalequivalent ductwork length using the approximate feetof equivalent length of some typical ducts.5Installation Instructions