Download INSTALLATION MANUAL MANUEL D'INSTALLATION

EQUIVALENT DUCT LENGTHS FOR COMMONLY USED TRANSITIONS
Size of Duct
Piece (in)
Equivalent
Length (ft)
6
1.2
7
0.95
8
0.7
10
0.6
3¼" x 10"
Straight
N/A
3¼" x 14"
Straight
Duct Piece
Smooth
Straight
90° Elbow
Round
45° Elbow
Round
Size of Duct
Piece (in)
Equivalent
Length (ft)
6
10
7
5
3¼" x 10"
Center Reverse
Elbow Left
N/A
15
1
3¼" x 10"
Center Reverse
Elbow Right
N/A
25
N/A
0.7
3¼" x 10" Left
Reverse Elbow
N/A
15
6
12
N/A
25
7
8
3¼" x 10"
Right Reverse
Elbow
8
6
6
2
7
2
6
5
7
4
8
2
8
3
10
2
6
2
7
2
8
2
2' Long
3¼" x 10"
Flex
N/A
20
3¼" x 10"
to Round
10
1
7" Inline
Backdraft
Damper
7
3¼" x 10"
90° Elbow
Round
N/A
5
3¼” x 10"
45° Elbow
Round
N/A
15
3¼" x 10"
Flat Elbow
Round to
3¼" x 10"
3¼" x 10"
to Round
Round to
3¼" x 10"
90° Elbow
N/A
Duct Piece
3¼" x 10"
to Round
90° Elbow
Round
Wall Cap
Round
Roof Cap
20
6
1
7
1
6
5
7
3
6
10
7
8
3¼" x 10"
Roof Jack
and Shutter
N/A
NOTE: These commonly used installation parts can be purchased
at a local hardware store. THERMADOR® does not manufacture all
these parts.
Table 4: Duct Lengths
English 8