American Dryer AD-202 Installation Manual page 28

202DR MULTIPLE DRYER VENTING WITH 12-INCHES (30.4 CM) DIAMETER
IMPORTANT: 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
(6.1 meters) more than the original limitations of 20 feet (6.1 meters) with two (2)
elbows. When the ductwork approaches the maximum limits as noted in this manual,
a professional heating, ventilating, and air-conditioning (HVAC) firm should be
consulted for proper venting information.
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 (0.74 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 inch water column. Where employed, booster fans must not activate the dryer airflow
proving switch (sail switch) when the dryer is not in operation.
The ductwork 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 duct.
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EXHAUST CONNECTIONS AT COMMON DUCT
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