Installation, Calculating duct length table – Electrolux EI30DD10KS User Manual
Page 14
14
Installation
Calculating Duct Length Table
For maximum efficiency, use the shortest and straightest duct possible. The system will operate most
efficiently when the ductwork does not exceed 60 feet of equivalent duct. The downdraft will operate
properly with ductwork up to 100 equivalent feet of duct.
Calculations are approximate and based on HVAC industry standards.
TOTAL DUCTWORK
Ft. or m
EQUIVALENT
LENGTH X
NUMBER
USED =
EQUIVALENT
LENGTH
m
r
o
.
t
F
Straight
m
r
o
.
t
F
)
m
3
(
.t
F
0
1
90° Elbow
m
r
o
.
t
F
15 Ft. (4.6m)
90° Flat Elbow
m
r
o
.
t
F
)
m
9
(
.t
F
0
3
m
r
o
.
t
F
25 Ft. (7.6m)
Wall Cap with Damper
m
r
o
.
t
F
)
m
5
.
1
(
.t
F
5
m
r
o
.
t
F
)
m
5
.
1
(
.t
F
5
45° Elbow
8" or 10” (20.3cm or 25.4cm)
ROUND DUCT PIECES
3¼" x 14" (8.2cm x 35.6cm)
RECTANGULAR DUCT PIECES
m
r
o
.
t
F
Straight
m
r
o
.
t
F
)
m
5
4
.
0
(
.t
F
5
.
1
Round Metal Flex - No Bends
m
r
o
.
t
F
)
m
3
(
.t
F
0
1
90° Elbow
m
r
o
.
t
F
)
m
5
.
1
(
.t
F
5
45° Elbow
8” (20.3cm) Round to Rectangular
Transition 90° Elbow
8” (20.3cm) Round to Rectangular
Transition
m
r
o
.
t
F
25 Ft. (7.6m)
Round Wall Cap with Damper
25 Ft. (7.6m)
m
r
o
.
t
F
Round Roof Cap
5 Ft. (1.5m)
m
r
o
.
t
F
10” to 8” Transition
Measure length of Straight
duct and write here
Measure length of Straight
duct and write here