9
Multiple Dryer Venting
n
A main vent can be used for venting a group of dryers. Main
vent should be sized to remove 5663 l/min (200 CFM) of air
per dryer. Large-capacity lint screens of proper design may
be used in the main vent if checked and cleaned frequently.
The room where the dryers are located should have make-up
air equal to or greater than the airflow of all the dryers in the
room.
n
A back-draft damper kit is needed and is available from a
commercial laundry distributor; it should be installed in the
vent of each dryer to keep exhausted air from returning
into the dryers and to keep the exhaust in balance within
the main vent. Unobstructed return air openings are required.
Each vent should enter the main vent at an angle pointing in the
direction of the airflow. Vents entering from the opposite side
should be staggered to reduce the exhausted air from interfering
with the other vents.
The maximum angle of each vent entering the main vent should
be no more than 30°.
Keep air openings free of dry cleaning fluid fumes. Fumes create
acids which, when drawn through the dryer heating units, can
damage dryers and items being dried.
A clean-out cover should be located on the main vent for periodic
cleaning of the vent system.
If an exhaust hood cannot be used:
The outside end of the main vent should have a sweep elbow
directed downward. If the main vent travels vertically through the
roof, rather than through the wall, install a 180° sweep elbow on
the end of the vent at least 2 ft. (610 mm) above the highest part
of the building. The opening in wall or roof shall have a diameter
1/2" (13 mm) larger than the vent diameter. The vent should be
centered in the opening.
Do not install screening or cap over the end of the vent.
IMPORTANT:
Observe all governing codes and ordinances.
Use a heavy metal vent. Do not use plastic or metal foil vent.
Rigid metal vent is recommended for best drying performance
and to avoid crushing and kinking.
Flexible metal vent must be fully extended and supported when
the dryer is in its final position. Remove excess flexible metal vent
to avoid sagging and kinking that will result in reduced airflow
and poor performance.
The total length of flexible metal vent should not exceed 7
3
⁄
4
ft.
(2.4 m).
An exhaust hood should cap the vent to keep rodents and
insects from entering the building.
Exhaust hood must be at least 12" (305 mm) from the ground
or any object that may be in the path of the exhaust (such as
flowers, rocks, bushes, or snow).
If using an existing vent system, clean lint from the entire length
of the system and make sure exhaust hood is not plugged with
lint. Replace any plastic or metal foil vent with rigid metal or
flexible metal vent.
Plan installation to use the fewest number of elbows and turns.
Allow as much room as possible when using elbows or making
turns. Bend vent gradually to avoid kinking.
Vent outlet is located at the center of the bottom dryer back.
The vent can be routed up, down, left, right, behind the dryer,
or straight out the back of the dryer.
Vent System Length
Maximum length of vent system depends upon the type of vent
used, number of elbows, and type of exhaust hood.
If dryer is installed in a confined area, such as a bedroom
or bathroom, provision must be made for enough air for
combustion and ventilation. (Check governing codes and
ordinances.) See “Recessed Area Installation Instructions”
in the “Location requirements” section.
A 4" (102 mm) outlet hood is preferred. However, a 2
1
⁄
2
"
(64 mm) outlet exhaust hood may be used. A 2
1
⁄
2
" (64 mm)
outlet creates greater back pressure than other hood types.
For permanent installation, a stationary vent system is required.
30˚ max.
air flow
A. Individual dryer vent
B. Main vent
A
B
12" min.
(305 mm)
24" min.
(610 mm)
A
A. Exhaust hood or elbow
B. Wall
C. Main collector vent
D. Horizontal vent
E. 180° sweep elbow
F. Vertical vent
G. Roof
E
B
G
C
D
24" (610 mm)
min. above
highest point
of building
F
C
Min. 12" (300 mm)
clearance above any
accumulation of snow, ice,
or debris such as leaves.
Rigid Metal Vent
No. of 90° turns
4" (102 mm) Exhaust Hoods
Maximum Vent Length
0
1
2
3
4
Box Hood and Louvered Style Angled Hood Style
130 ft. (39.6 m)
125 ft. (38.1 m)
115 ft. (35.1 m)
106 ft. (32.3 m)
98 ft. (29.9 m)
129 ft. (39.3 m)
119 ft. (36.3 m)
109 ft. (33.2 m)
100 ft. (30.5 m)
92 ft. (28 m)
Box
Louvered
2
1
⁄
2
" (64 mm) Angled
A
B
Exhaust Air Flow
A. Good
B. Better
