Outside Ductwork Protection

Important

! Exhaust back pressure measured by a manometer/magnehelic in the exhaust duct must

be no less than 0 and must not exceed 0.6 in wc (1.48 mb).

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.

As per the National Fuel Gas Code, “Exhaust ducts for type 2 clothes dryers shall be constructed of sheet metal or other noncombustible material. Such ducts shall be equivalent in strength and corrosion resistance to ducts made of galvanized sheet steel not less than 26 gauge (0.0195-inches [0.50 mm]) thick.”

The ductwork for this appliance must be suitable for the appliance category in accordance with national installation regulations of the country of destination.

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

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.

Horizontal Venting

When horizontal dryer venting is used, the length of the ductwork from the dryer to the outside exhaust outlet, must not exceed 20 feet (6.10 meters). The minimum diameter of this ductwork must be at least 6-inches (15.24 cm) for M31SL and 8-inches (20.32 cm) for M50SL and M75SL. Including tumbler/dryer elbow connections or elbows used for outside protection from the weather, no more than 1 elbow should be used in the exhaust duct run. If more than 1 elbow is used, the cross-sectional area of the ductwork must be increased.

Vertical Venting

When vertical dryer venting is used, the length of the ductwork from the dryer to the outside exhaust outlet, must not exceed 12 feet (3.66 meters). The minimum diameter of this ductwork must be at least 6-inches (15.24 cm) for M31SL and 8-inches (20.32 cm) for M50SL and M75SL. Including tumbler/dryer elbow connections or elbows used for outside protection from the weather, no more than 3 elbows should be used in the exhaust duct run. If more than 3 elbows are used, the cross-sectional area of the ductwork must be increased.

A	=	20 feet (6.10 meters)	C	=	12 feet (3.66 meters)
B	= M31SL: 6-inches (15.24 cm)		D	= M31SL: 6-inches (15.24 cm)
		M50SL, M75SL: 8-inches (20.32 cm)			M50SL, M75SL: 8-inches (20.32 cm)

NOTE 1 Opening from combustible materials must be 2-inches (5.08 cm) larger than the duct (all the way around). The duct must be centered within this opening.

NOTE 2 Distance should be 2 times the diameter of the duct to the nearest obstruction.

Multiple Dryer (Common) Venting

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.

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 45º in the direction of airflow. The main duct should be tapered, with the diameter increasing before each individual duct is added.

American Dryer Corp.

113431 - 10