E. EXHAUST REQUIREMENTS
Exhaust duct work should be designed and installed by a qualified professional. Improperly sized duct work will create excessive back pressure which results in slow drying, increased use of energy, and shutdown of the burner by the airflow (sail) switch, burner
Where possible, it is suggested to provide a separate (single) exhaust duct for each dryer.
CAUTION: IMPROPERLY SIZED OR INSTALLED EXHAUST DUCT WORK CAN CREATE A POTENTIAL FIRE HAZARD.
CAUTION: DRYER MUST BE EXHAUSTED TO THE OUTDOORS.
The exhaust duct work should be laid out in such a way that the duct work travels as directly as possible to the outdoors with as few turns as possible. The shape of the duct work is not critical so long as the minimum cross section area is provided. Single or independent dryer venting is recommended.
It is suggested that the use of 90° turns be avoided; use 30° or 45° angles instead.
The duct work should be smooth inside with no projections from sheet metal screws or other obstructions which will collect lint. When adding ducts, the ducts to be added should overlap the duct to which it is connected. ALL duct work joints must be taped to prevent moisture and lint from escaping into the building. Additionally, inspection doors should be installed at strategic points in the exhaust duct work for periodic inspection and cleaning.
IMPORTANT: When connecting duct work to the dryer exhaust duct, be sure that when screws are used they do not restrict the operation (both opening and closing) of the damper.
NOTE: When the exhaust duct passes through a wall, ceiling, or roof made of combustible materials, the opening must be 2 inches larger (all the way around) than the duct. The duct must be centered within this opening.
To protect the outside end of horizontal duct work from the weather, a 90° elbow bent downward should be installed where the exhaust exits the building. If the duct work 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 (i.e., roof or ground level).
IMPORTANT: DO NOT use screens or caps on the outside of opening of exhaust duct work.
IMPORTANT: Exhaust back pressure measured by a manometer at the dryer exhaust duct area must not exceed 0.3 inches of water column (W.C.).
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