Duct Length - Kenmore 721.62774100 Installation Instructions Manual

STEP 2:
PREPARE THE VENTING SYSYTEM
STANDARD FITTINGS
NOTE: If the existing duct is round, you must use a rectangular-to-round adapter, with a rectangular 3"
extension duct installed between the damper assembly and the adapter to prevent the exhaust
damper sticking.
DUCT LENGTH
The total length of the duct system, including straight duct, elbows, transitions, wall or roof caps must not
exceed the equivalent of 140 feet.
For best performance, do not use more than three 90 degree elbows.
Below are the standard fittings and their equivalent length in feet.
3 1/4"x10"
to 6"=5ft.
2
3 1/4"x10" roof
cap=24ft.
3
3 1/4"x10" 90 °
elbow=25ft.
90 ° elbow
=1Oft.
5
3 1/4"x10"
wall cap
=40ft.
6
45 ° elbow
=5ft.
7
3 1/4"x10"
flat elbow
= 10ft.
Figure 9
To calculate the equivalent length of each duct piece used, see the examples below.
For 3 1/4"x10" SYSTEMS
301/4;;b17' w _ 6ft. _ wall cap
}rz ,
1-3 1/4" x 10" 90 ° elbow
1-Wall Cap
8 feet straight duct
TOTAL LENGTH
I
Examples
25 ft.
40 ft.
8ft.
73 ft.
For 6" ROUND SYSTEMS
wall cap
90 ° elbows _ 6ft. "-_1_
transi_
1-transition = 5 ft.
2-90 ° elbows = 20 ft.
1-Wall Cap = 40 ft.
8 feet straight = 8 ft.
TOTAL LENGTH = 73 ft.