4
Venting Requirements
Venting systems for Whirlpool dryers must meet the following
requirements:
■
The capacity to handle 200 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 in which 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]).
All Whirlpool electric dryer models, including “long vent dryers,”
that are sold in the United States and Canada are UL listed
(reference UL2158 standard), and all Whirlpool gas dryer models
are CSA listed (reference ANSI Z21.5.1 standard). These
standards require testing at the maximum-rated exhaust vent
conditions that are published in the product literature for each
individual model. The designation for the UL or CSA listing can
be found on or adjacent to the serial label on the product.
“AF” Code
Certain electronic dryer models have airflow detection
capabilities. (See specific model product literature for details). If
the airflow in the dryer is extremely low, an “AF” code will be
displayed on the control panel. For single dryer venting systems,
this code means that you may have a blocked or partially blocked
vent or that your overall vent system length is too long. To resolve
this issue:
■
Check to see if the vent run from the dryer to the wall is
crushed. Refer to the “Venting Requirements” section of
the Use and Care Guide for more information.
■
Confirm that the vent run from the dryer to the wall is free
of lint and debris.
■
Confirm that the exterior vent exhaust hood is free of lint
and debris.
■
Confirm that your vent system falls within the
recommended run length and number of elbows for the
type of vent you are using. Refer to the “Plan Vent
System” section of the Use and Care Guide for details.
■
Select a Timed Dry heated cycle, and restart the dryer.
■
If the message persists, have your entire home venting
run cleaned.
For multi-dryer venting systems, the “AF” code means that your
vent may be blocked or partially blocked or that the venting
system is creating back pressure in excess of the maximum
allowable 0.6” (1.5 cm) water column. In this case, the
engineering firm that designed the system should be consulted.
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
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
1"*
(2.5 cm)
