ADC AD-120ES Installation Manual page 16

AD-120ES and ADG-120DR
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 and should be spaced at least
48-3/4" (123.83 cm) apart. The main duct should
be tapered, with the diameter increasing before
each individual dryer branch duct is added.
IMPORTANT: No more than four dryers should be
connected to one main common duct.
The main duct may be any shape or cross-sectional
area, as long as the minimum cross section area is
provided. The illustrations on the right show the
minimum cross section area for multiple dryer round
or square venting. These figures must be increased
10 square inches (64.51 square centimeters) when
rectangular main ducting is used, and the ratio of
duct width to depth should not be greater than
3-1/2 to 1. These figures must be increased in
proportion if the main duct run to the last dryer to
where it exhausts to the outdoors is unusually long
(over 20 feet [6.09 meters]) or has numerous elbows
(more than two) in it. In calculating ductwork size,
the cross section area of a square or rectangular
duct must be increased twenty percent for each
additional 20 feet (6.09 meters). The diameter of a
round exhaust must be increased ten percent for
each additional 20 feet (6.09 meters). Each 90°
elbow is equivalent to an additional 15 feet (4.57
meters).
IMPORTANT: Exhaust back pressure measured by
a manometer at each dryer exhaust duct area must
be no less than 0 and must not exceed 0.3 in WC
(0.75 mb, 75 Pa).
For extended ductwork runs, the cross section area
of the ductwork can only be increased to an extent.
Maximum proportional ductwork runs cannot
exceed 20 feet (6.09 meters) more than the original
limitations of 20 feet (6.09 meters) with two elbows.
When the ductwork approaches the maximum limits
as noted in this manual, a professional HVAC firm
should be consulted for proper venting information.
The duct should be smooth inside with no
projections from sheet metal screws or other
obstructions, which will collect lint. When adding
ducts, the duct to be added should overlap the duct
to which it is to be 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.
NOTE: When the exhaust ductwork passes through
a wall, ceiling, or roof made of combustible
materials, the opening must be 2-inches (5.08 cm)
larger than the duct (all the way around). The duct
must be centered within this opening.
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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 exhaust 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 nearest obstruction.
IMPORTANT: Do not use screens, louvers, or caps on the outside
opening of the exhaust ductwork.
AD-120ES MULTIPLE DRYER VENTING
14-INCHES (35.56 CM) DIAMETER, 2,150 CFM (60.88 CMM)
EXHAUST CONNECTION AT COMMON DUCT
(GAS, ELECTRIC, AND STEAM MODELS)
ADG-120DR MULTIPLE DRYER VENTING
ADG-120DR 12-INCHES (30.48 CM) DIAMETER (1,750 CFM [49.6 CMM])
EXHAUST CONNECTIONS AT COMMON DUCT
American Dryer Corp. 113386- 28