American Dryer Corp. MLG32PDB - Manual (Page 18)

14 Maytag Co. 113062 - 16
2. 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 the airflow.
IMPORTANT: No more than eight (8) dryers should be connected to one (1) main common duct.
NOTE: Refer to the illustration on the next page for examples of multiple dryer (common) venting.
The main duct may be any shape so long as the minimum cross-sectional area is provided. The illustration
on the next page shows the minimum cross-sectional area for multiple dryer venting. These figures must
be increased in proportion if the main duct run from the last dryer to where it exhausts to the outdoors is
unusually long (over 20 feet) or has numerous elbows (more than one [1]) in it.
IMPORTANT: For extended ductwork runs, the cross-sectional area of the ductwork can only be
increased to an extent. Maximum proportional ductwork runs cannot exceed 20 feet
more than the original limitations of 20 feet with one (1) elbow. When the ductwork
approaches the maximum limits as noted in this manual, a professional heating,
ventilation, and air-conditioning (HVAC) firm should be consulted for proper venting
information.
IMPORTANT: Exhaust back pressure measured by a manometer at the dryer’s exhaust duct area
must be no less than 0 and must not exceed 0.3 inches of water column (W.C.)
when both baskets (tumblers) are operating.
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. Also, inspection doors should be installed at strategic points in the exhaust ductwork for periodic
inspection and cleaning.
NOTE: When the exhaust ductwork passes through a wall, ceiling, or roof made of combustible
materials, the opening must be 2-inches larger than the duct (all the way around). The duct
must be centered within this opening.
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.