Standard Fittings; Duct Length - Kenmore 721.80494 Installation Instructions Manual

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.
90˚ elbow = 10ft.
To calculate the equivalent length of each duct piece used, see the examples below.
For 3-1/4"x10" SYSTEMS
3-1/4"x10"
90˚ elbow
2ft.
1 3-1/4" x 10" 90˚ elbow
1 wall cap
8 feet straight duct
TOTAL LENGTH
STEP 2:
PREPARE THE VENTING SYSTEM
3-1/4"x10" roof cap = 24ft.
3-1/4"x10" wall cap
= 40ft.
6ft.
wall cap
= 25 ft.
= 40 ft.
= 8 ft.
= 73 ft.
45˚ elbow = 5ft.
Figure 9
Examples
For 6" ROUND SYSTEMS
90˚ elbows
transition
1 transition
2 90˚ elbows
1 wall cap
8 feet straight
TOTAL LENGTH
3-1/4"x10" 90˚ elbow = 25ft.
3-1/4"x10" flat elbow
= 10ft.
wall cap
6ft.
2ft.
=
=
=
=
=
5 ft.
20 ft.
40 ft.
8 ft.
73 ft.
9