Empire Comfort Systems DVLXG55BP90N Installer's Manual page 39

EFFECTIVE LENGTH POST FAN IS CALCULATED BY THE
FOLLOWING EQUATION:
Equation 2
NOTE: Blower Height is from closest horizontal surface below
fan.
Effective Duct Length = Vertical Run Up + (2 x Vertical Run
Down) + L1 + L2 + L3 + (3 x # of 90° bends) + (1.5 x # of 45°
bends)
Blower
Height
H 1 0
H 2 0
H 3 0
Vertical Run Up = (Blower Height + V1) = 0
Vertical Run Down = 0ft.
Horizontal Length 1 = (12ft. + 0ft. + 0ft.) + (3 x 2) + (1.5 x 1) =
(12ft. +0ft. + 0ft.) = 12ft.
Horizontal Length 2 = (4ft. + 6ft. + 1.5ft.) + (3 x 2) + (1.5 x 1) =
(11.5ft. +6ft. + 1.5ft.) = 20ft.
Horizontal Length 3 = (4.5ft. + 6ft. + 6ft.) + (3 x 2) + (1.5 x 1) =
(16.5ft. +6ft. + 1.5ft.) = 24ft.
DUCT VENT INSTALLATION
L
L
H1
Ceiling/Wall
Register
R
Outlet
L
EXAMPLE 2
L₁ L₂ L₃
12ft 0 0
4ft 6ft 1.5ft
4.5ft 6ft 6ft
H3
R
L
R
L
R
R
L
L
R
6" Wire Reinforced Ducting
L
(insulated recommended)
H2
45° 90°
Bends Bends Effective
0 0
1 2
1 2
Effective Combined length = Combined Horizontal Run +
length of 10" ducting
Effective Combined length = (H1 + H2 +H3) + L4
Effective Combined length = (12ft. + 20ft. + 24ft.) + 4ft.
Total Effective Combined Length = 60ft
10" Wire Reinforced Ducting
(insulated recommended)
Total
Length
12ft
20ft
24ft
39