Frigidaire FH36DD50MS Use and Care Manual - Page 12

INSTALLATION Calculating Duct Length Table For maximum efficiency, use the shortest and straightest duct possible. The system will operate most efficiently when the ductwork does not exceed 60 feet of equivalent duct. The downdraft will operate properly with ductwork up to 100 equivalent feet of duct. Calculations are approximate and based on HVAC industry standards. DUCT PIECES EQUIVALENT LENGTH X NUMBER USED = EQUIVALENT LENGTH 6" (15.2cm) Round Straight ** 1 Ft. (0.3m) Ft. or m 6" (15.2cm) Round Metal Flex No Bends ** 1.5 Ft. (0.45m) Ft. or m 6" (15.2cm) 90° Elbow 10 Ft. (3m) Ft. or m 6" (15.2cm) 45° Elbow 3¼" x 10" (8.2cm x 25.4cm) Straight ** 3¼" x 10" (8.2cm x 25.4cm) 90° Elbow 3¼" x 10" (8.2cm x 25.4cm) 45° Elbow 3¼" x 10" (8.2cm x 25.4cm) 90° Flat Elbow 3¼" x 10" (8.2cm x 25.4cm) to 6" (15.2cm) Round Transition 90° Elbow 6" (15.2cm) Round to 3¼" x 10" (8.2cm x 25.4cm) Transition 90° Elbow 3¼" x 10" (8.2cm x 25.4cm) to 6" (15.2cm) Round Transition 6" (15.2cm) Round to 3¼" x 10" (8.2cm x 25.4cm) Transition 6" (15.2cm) Round Wall Cap with Damper 3¼" x 10" (8.2cm x 25.4cm) Wall Cap with Damper 5 Ft. (1.5m) 1 Ft. (0.3m) 10 Ft. (3m) 5 Ft. (1.5m) 10 Ft. (3m) 30 Ft. (9m) 30 Ft. (9m) 5 Ft. (1.5m) 5 Ft. (1.5m) 30 Ft. (9m) 30 Ft. (9m) 6" (15.2cm) Round Roof Cap 30 Ft. (9m) Ft. or m Ft. or m Ft. or m Ft. or m Ft. or m Ft. or m Ft. or m Ft. or m Ft. or m Ft. or m Ft. or m Ft. or m TOTAL DUCTWORK 12 ** For Straight Round / Rectangular Duct, measure actual linear feet used and then multiply by Equivalent Length shown. Ft. or m