Standard Fittings; Duct Length - LG LMV1635SBQ 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.
1
4
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
2
3 1/4"x10" 3 1/4"x10" roof
to 6"=5ft.
5
3 1/4"x10"
wall cap
90˚ elbow
=40ft.
=10ft.
Figure 9
6ft.
wall cap
= 25 ft.
= 40 ft.
= 8 ft.
= 73 ft.
3
3 1/4"x10" 90˚
cap=24ft. elbow=25ft.
6 7
3 1/4"x10"
flat elbow
45˚ elbow
=5ft.
Examples
For 6" ROUND SYSTEMS
90˚ elbows
transition
1-transition
2-90˚ elbows
1-Wall Cap
8 feet straight
TOTAL LENGTH
— 9 —
=10ft.
wall cap
6ft.
2ft.
=
=
=
=
=
5 ft.
20 ft.
40 ft.
8 ft.
73 ft.