Thermador HMWN30 Manuel D'installation page 7

Us e this chart to compute maximum
permissable lengths for duct runs to
outdoors .
Note: Do not exceed maximum permissable
equivalent lengths!
Maximum recommended duct
length for these hoods: 150 feet
Fl exible ducting:
If flexible metal ducting is used, all
the equivalent feet values in the table
should be doubled. The flexible
metal duct should be straight and
smooth and extended as much as
possible.
Do NOT use flexible plastic ducting.
Any home ventilation system, such as a
Note:
gas furnaces, gas water heaters and other naturally
vented systems. To minimize the chance of interruption
of such naturally vented systems, follow the heating
equipment manufacturer's guidelines and safety
standards such as those published by NFPA and ASHRAE.
*Hoods are supplied with a 10"
round transition. A locally
supplied transition is required
for other sizes.
Note: Outlet on top of hood is
8-1/8" x 8".
Table 1. Ventilator performance calculation
D c u P t e i e c
10" round
to 8" roun d
Round ,
straight
3-1/4" x 10"
3-1/4" x 12 "
straight
90° elbo w
45° elbo w
3 -1⁄4" x 12"
3-1/4" x 10"
90° elbow
3-1/4" x 10 "
3-1/4" x 12 "
45° elbow
3-1/4" x 10"
3-1/4" x 12"
90° flat elbow
10"round transition
to 3-1/4" x 10" or
3-1/ 4" x 12"
3-1/4" x 10" or
3-1/4" x 12" to
10" round transiti on
10" round to 3-1/4" x 10"
3-1/4" x 12" transition
90° elbow
3-1/4" x 10 "
3-1/4" x 12" t o 10" round
transiti on 90° elbow
Roun d
wall c ap
with damper
3-1/4" x 10"
3-1/4" x 12" wall cap
with damper
Round
roof cap
7
5 ft.
1 ft.
(per foot
length)
1 ft.
(p er f oot
length)
8" Di a. 17 ft.
10" Dia. 24 ft .
8" Di a. 10 ft.
10" Dia. 14 ft .
15 ft.
14 ft.
8 ft.
9 ft.
33 ft.
36 ft.
9 ft.
6 ft.
16 ft.
13 ft.
9 ft.
8 ft.
8" Dia. 32 ft.
10" Dia. 41 ft.
24 ft.
26 ft.
8" Dia. 44 ft.
10" Di a. 56 ft .
Total Duct Run