Maytag Commercial MLG30 Manuel D'installation page 7

The ductwork should be laid out in such a way that the
ductwork travels as directly as possible to the outdoors with
as few turns as possible. Single or independent dryer venting
is recommended. It is suggested that the use of 90° turns be
avoided; use 30° and/or 45° bends instead. The radius of the
elbows should preferably be 1-1/2 times the diameter of the
duct. All ductwork should be smooth inside with no projections
from sheet metal screws or other obstructions, which will collect
lint. When adding ducts, overlap the duct being connected.
All ductwork joints must be taped to prevent moisture and lint
from escaping into the building. Inspection doors should be
installed at strategic points in the exhaust ductwork for periodic
inspection and cleaning of lint from the ductwork.
IMPORTANT: Exhaust back pressure measured by a
manometer/magnehelic in the exhaust duct must be no less
than 0 and must not exceed 0.3 in WC (0.75 mb).
NOTE: It is recommended that exhaust or booster fans not be
used in the exhaust ductwork system except where necessary
to maintain exhaust back pressure (in the exhaust duct) between
zero and 0.3" water column. Where employed, booster fans
must not activate the dryer airflow proving switch (sail switch)
when the dryer is not in operation.
NOTE: When the exhaust ductwork passes through a wall,
ceiling, or roof made of combustible materials, the opening must
be 2" (5.08 cm) larger than the duct (all the way around). The
duct must be centered within this opening.
The ductwork for this dryer must be suitable for the appliance
category in accordance with national installation regulations of
the country of destination.
Outside Ductwork Protection
To protect the outside end of the horizontal ductwork from the
weather, a 90° elbow bent downward should be installed where
the exhaust exits the building. If the ductwork travels vertically
up through the roof, it should be protected from the weather by
using a 180° turn to point the opening downward. In either case,
allow at least twice the diameter of the duct between the duct
opening and the nearest obstruction (refer to the diagram).
IMPORTANT: Do not use screens, louvers, or caps on the
outside opening of the exhaust ductwork.
Single Dryer Venting (8" Duct)
IMPORTANT: A minimum exhaust duct size of 8" (20.3 cm)
must be used.
For an 8" (20.3 cm) run where a maximum of two elbows are
used (refer to the illustration below), the ductwork from the dryer
outlet must not exceed 10' (3.0 m).
This calculation of 10' (3.0 m) compensates or allows for the use
of a maximum of two elbows. Refer to the illustration below.
SINGLE DRYER VENTING
8" (20.32 cm) RND DUCT
NOTE A
ROOF
2 x D CLEARANCE
10 FEET
MAXIMUM
(3.05 m)
INSPECTION
VERTICAL
NOTE A OPENING MUST BE 2"(5.08 cm) LARGER THAN THE DUCT (ALL THE
WAY AROUND). THE DUCT MUST BE CENTERED WITHIN THIS OPENING
10 FEET MAXIMUM (3.05 m)
INSPECTION
DOOR
2 x D CLEARANCE
DOOR
HORIZONTAL
If the length of the duct run or quantity of elbows used exceeds
the above noted specifications, the cross-sectional area of the
ductwork may need to be increased.
IMPORTANT: For extended ductwork runs, the cross section
area of the ductwork can only be increased to an extent. When
the ductwork approaches the maximum limits noted in this
manual, a professional HVAC firm should be consulted for
proper venting information.
Single Dryer Venting (10" Duct)
IMPORTANT: A minimum exhaust duct size of 10" (25.4 cm)
must be used for extended runs.
For a 10" (25.4 cm) run where a maximum of two elbows are
used (refer to the illustration below), the ductwork from the dryer
outlet must not exceed 45' (13.7 m).
This calculation of 45' (13.7 m) compensates or allows for the
use of a maximum of two elbows. Refer to the illustration below.
2 x D CLEARANCE
8"(20.3 cm)
DRYER
CONNECTION
VERTICAL
NOTE A OPENING MUST BE 2"(5.08 cm) LARGER THAN THE DUCT (ALL THE
WAY AROUND). THE DUCT MUST BE CENTERED WITHIN THIS OPENING
If the length of the duct run or quantity of elbows used exceeds
the above noted specifications, the cross-sectional area of the
ductwork may need to be increased.
IMPORTANT: For extended ductwork runs, the cross section
area of the ductwork can only be increased to an extent. When
the ductwork approaches the maximum limits noted in this
manual, a professional HVAC firm should be consulted for
proper venting information.
Multiple Dryer (Common) Venting
If it is not feasible to provide separate exhaust ducts for each
dryer, ducts from individual dryers may be channeled into a
"common main duct." The individual ducts should enter the
bottom or side of the main duct at an angle not more than 45° in
the direction of airflow. The main duct should be tapered, with
the diameter increasing before each individual 10" (25.4 cm)
duct (when dryer common exhaust is used) is added.
NOTE A
IMPORTANT: No more than four dryers or eight tumblers total
8" (20.32 cm)
should be connected to one main common duct.
RND DUCT
The main duct may be any shape provided that the minimum
cross-sectional area is maintained. The illustration below shows
the minimum cross-sectional area for multiple dryer venting.
These figures must be increased if the main duct run from the
last dryer to where it exhausts to the outdoors is unusually long
(over 30' [9.1 m]) or has numerous elbows (more than one) in it.
SINGLE DRYER VENTING (10" DUCT)
10"(25.4 cm) RND DUCT
ROOF
NOTE A
45 FT
MAX
(13.7 m)
8"(20.3 cm)
INSPECTION
DRYER
DOOR
CONNECTION
45 FT MAX
(13.7 m)
INSPECTION
NOTE A
DOOR
10"(25.4 cm)
DUCT
2 x D CLEARANCE
HORIZONTAL
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