Installation Instructions
DUCTWORK CALCULATIONS
Calculate Total Equivalent Ductwork Length
| Equivalent | Number | Equivalent | ||
Duct Pieces | Length* x | Used = | Length | ||
5″ round |
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straight | 2.7 ft. | x | ( | ft.)† = | ft. |
6″ round |
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straight | 1 ft. | x | ( | ft.)† = | ft. |
31⁄4″ x 10″ |
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straight | 1 ft. | x | ( | ft.)† = | ft. |
5″, 90° |
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elbow | 37 ft. | x | ( | ) = | ft. |
6″, 90° |
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elbow | 12 ft. | x | ( | ) = | ft. |
5″, 45° |
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elbow | 18 ft. | x | ( | ) = | ft. |
6″, 45° |
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elbow | 7 ft. | x | ( | ) = | ft. |
Flexible |
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metal offset | See Calculations in |
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adapter | Step 5A. |
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| ft. |
31⁄4″ x 10″ |
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90° elbow | 14 ft. | x | ( | ) = | ft. |
31⁄4″ x 10″ |
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45° elbow | 8 ft. | x | ( | ) = | ft. |
31⁄4″ x 10″ |
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90° flat elbow | 33 ft. | x | ( | ) = | ft. |
5″ round |
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to 31⁄4″ x 10″ |
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transition | 3 ft. | x | ( | ) = | ft. |
6″ round |
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to 31⁄4″ x 10″ |
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transition | 2 ft. | x | ( | ) = | ft. |
| Subtotal Column 1 = | ft. | |||
*Equivalent lengths of duct pieces are based on actual tests and reflect requirements for good venting performance with any downdraft cooktop.
†Measure and list feet of straight duct used. Count and list the quantity of all other duct pieces for the “Number Used” of each type.
IMPORTANT:
For maximum efficiency, use the shortest and straightest duct run possible, with as few fittings as possible. For satisfactory performance, the duct run should not exceed 100 feet equivalent length.
Venting performance is improved by using larger diameter duct.
| Equivalent | Number | Equivalent | ||
Duct Pieces | Length* x | Used | = | Length | |
5″ round |
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to 31⁄4″ x 10″ |
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transition |
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90° elbow | 37 ft. | x | ( | ) = | ft. |
6″ round |
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to 31⁄4″ x 10″ |
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transition |
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90° elbow | 4 ft. | x | ( | ) = | ft. |
31⁄4″ x 10″ |
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to 6″ round |
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transition | 2 ft. | x | ( | ) = | ft. |
31⁄4″ x 10″ |
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to 6″ round |
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transition |
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90° elbow | 4 ft. | x | ( | ) = | ft. |
Tapered 5″ |
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round to |
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6″ round |
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transition | 6 ft. | x | ( | ) = | ft. |
5″ round collar |
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to 6″ round |
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transition | 13 ft. | x | ( | ) = | ft. |
5″ round |
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wall cap |
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with damper | 84 ft. | x | ( | ) = | ft. |
6″ round |
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wall cap |
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with damper | 24 ft. | x | ( | ) = | ft. |
31⁄4″ x 10″ |
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wall cap |
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with damper | 24 ft. | x | ( | ) = | ft. |
6″ round |
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roof cap | 33 ft. | x | ( | ) = | ft. |
| Subtotal Column 2 = | ft. | |||
| Subtotal Column 1 = | ft. | |||
| TOTAL DUCTWORK = | ft. | |||
Should not exceed 100 feet.
If flexible metal ducting is used, all the equivalent feet values in the table should be doubled. The flexible metal duct should be straight and smooth and extended as much as possible.
DO NOT use flexible plastic ducting.
Vent installation should not exceed 100 feet equivalent length.
Blower is rated at 400 CFM at 0.1 inch of water back pressure.
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