Outside Ductwork Protection

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.

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 the nearest obstruction.

IMPORTANT: Do not use screens, louvers, or caps on the outside opening of the exhaust ductwork.

Single Dryer Venting

IMPORTANT: Minimum duct size for a gas, electric, or steam dryer with a vertical run and not more than 3 elbows (including dryer connection and outside outlets) is

16-inches (40.64 cm) for a round duct or 14-1/2” by 14-1/2” (36.83 cm by 36.83 cm) for a square duct. Duct size must not be reduced anywhere downstream of dryer.

ML-130

When venting horizontally, the ductwork from each dryer must be 14-inches (35.56 cm) and not exceed 20 feet (6.1 meters) with no more than 1 elbow (including dryer connections and outside exhaust outlets). If the ductwork exceeds 20 feet (6.1 meters) or has numerous elbows, the cross-sectional area of the ductwork must be increased in proportion to the length and number of elbows in it.

When venting vertically, the ductwork from each dryer must be a minimum of 16-inches (40.64 cm) and not exceed 20 feet (6.1 meters) with no more than 3 elbows (including dryer connections and outside exhaust outlets). If the ductwork exceeds 20 feet (6.1 meters) or has numerous elbows, the cross-sectional area of the ductwork must be increased in proportion to the length and number of elbows in it.

IMPORTANT: For extended ductwork runs, the cross section area of the duct can only be increased to an extent. When the ductwork approaches the maximum limits as 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 and should be spaced at least 48-3/8 inches (122.87 cm) apart. The main duct should be tapered, with the diameter increasing before each individual 14-inch (35.56 cm) minimum duct is added.

IMPORTANT: The dryer is not provided with a back draft damper. When exhausted into a multiple (common) exhaust line, a back draft damper must be installed at each dryer duct.*

No more than 4 dryers should be connected to 1 main common duct.

*Models manufactured as of September 24, 2001, have a damper in the dryer as a standard item.

The illustrations on the following page show the minimum cross-sectional area for multiple dryer round or square venting. These figures must be increased in proportion if the length of ducting from the last dryer to where it exhausts to the outdoors is over 20 feet (6.1 meters) or has more than 1 elbow in it.

IMPORTANT: For extended ductwork runs, the cross- sectional area of the ductwork can only be increased to an extent. When the ductwork approaches the maximum limits as noted in this manual, a professional HVAC firm should be consulted for proper venting information.

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 (0.74 mb) for the ML-130 model.

American Dryer Corp ML-130DR, ML-130 III Outside Ductwork Protection, Single Dryer Venting