Specifications

4
Venting Requirements
Venting systems for Whirlpool dryers must meet the following
requirements:
■ The capacity to handle 150 CFM of air for each dryer in the
system.
■ A back pressure of 0.0" (0 cm) to 0.6" (1.5 cm) of water
column when measured at the connection to the dryer.
Back pressure should be measured with an empty dryer, a clean
lint screen and with the dryer operating in the Air Only cycle (no
heat). Use an inclined manometer, such as Dwyer model 102 (0"-
2" (0 cm - 5.1 cm] range) or Dwyer model 172 (0"-1" (0 cm -
2.5 cm] range) to measure the back pressure. See the following
illustration.
Single Dryer Venting Systems
Single dryer venting systems are defined as systems that have
only one dryer unit attached to a residential-type 4" (10.2 cm)
diameter rigid metal vent system. For single dryer venting
systems, see the Installation Instructions that came with your
dryer to determine the allowable length and number of elbows for
the venting system. In cases where the Installation Instructions do
not address the vent length for the specific number of elbows
required for a particular application, the following calculations
may be used. (The total vent system length includes all straight
and curved portions of the vent system.):
■ For 90° elbows, reduce the allowable vent system length by
10 ft (3.05 m).
■ For 45° elbows, reduce the allowable vent system length by
6 ft (1.83 m).
For example, if the Installation Instructions state that a dryer is
allowed 40 ft (12.2 m) of total vent length with two 90° bends, and
the installation requires three 90° bends, the total allowable vent
length would be reduced by 10 ft (3.0 m) (from 40 ft [12.2 m] to
30 ft [9.1 m)]).
Multiple Dryer Venting Systems
Multiple dryer venting systems must be designed specifically for
each application.
NOTE: It is recommended that an architectural or HVAC
engineering firm be consulted for designing the dryer venting
system.
Connecting a number of dryers to a single vent system is
common in coin-laundry stores and in many apartment buildings.
Listed here are some requirements for examples of three different
multiple dryer venting systems.
Option 1 - Horizontal System
The most common is the horizontal system, in which banks of
dryers are all located in one room and vented through a common
duct. See the following illustration for an example of a generic
horizontal system.
*Minimum spacing required between dryers
Option 2 - Vertical System
The vertical system is used in some apartment buildings that have
a washer and dryer on each floor. Each dryer is exhausted into the
same central vertical duct. See the following illustration for an
example of a generic vertical system.
A. Dryer - empty and running on Air Only cycle
B. 12" (30.5 cm) min. of straight pipe - measure back
pressure from the center
C. To vent system
D. 0.6" (1.5 cm) water maximum back pressure
E. Inclined manometer
A
B
C
D
E
A. 4" (10.2 cm) diameter rigid metal back draft damper
A. 0.6" (1.5 cm) water column maximum back pressure
B. Weighted dampers
C. Individual dryer exhaust - on each floor
D. 0.1" (0.25 cm) water column maximum vacuum
E. Main duct
F. Barometric damper (use depends on exhaust
system design)
G. Source of outside air
A
1"*
(2.5 cm)
G
A
B
C
D
F
E
F
F