American Dryer Corp. AD-385 - Manual (Page 17)

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, overheating of the dryer, and shutdown of the burner by the airflow (sail) switches,
burner hi-limits, or basket (tumbler) hi-heat thermostats.
CAUTION: DRYER MUST BE EXHAUSTED TO THE OUTDOORS.
CAUTION: IMPROPERLY SIZED OR INSTALLED EXHAUST DUCT WORK CAN
CREATE A POTENTIAL FIRE HAZARD.
The 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. Single or independent dryer venting is
recommended.
The dryer is manufactured with an 8" exhuast duct outlet. When single drying venting is used
an 8" exhaust duct can be used providing that the duct work from the dryer to the outside
exhaust outlet does not exceed ten (10) feet and there is no more than one (1) elbow (which is
the outside exhaust outlet protection). See illustraion A on page 14 for details. For exhaust
ducting which exceeds ten (10) feet, the minimum diameter of this duct must be at least 10
inches (even though the dryer exhaust duct outlet is only 8"). See illustrations B and C on page
15 for examples. In the case of multiple (common) dryer venting, the distance from the last
dryer to the outside exhaust duct outlet should not exceed twenety (20) feet. The shape of the
duct work is not critical so long as the minimum cross-sectional area is provided. It is sug­
gested that the use of 90 degree turns be avoided; use 30 degree and/or 45 degree angles in­
stead. The radius of the elbows should prefereably be 1-1/2 times the diameter of the duct.
Including basket (tumbler)/dryer elbow connections or elbows used for outside protection
from the weather, no more than two (2) elbows should be used in the exhaust run. If more than
two (2) elbows are used, the cross sectional area of the duct work must be increased.
ALL duct work 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 duct work joints must be taped to prevent
moisture and lint from escaping into the building. Inspection door should be installed at
strategic points in the exhaust duct work for periodic inspection and clean-out of lint from the
duct work.
IMPORTANT; Exhaust back pressure measured by a manometer in the exhaust duct
should not exceed 0.3 inches of water column.
IMPORTANT: For exhaust runs over 10 feet, minimum duct work diameter is 10-inches.
NOTE: Where the exhaust duct work passes through a wail, 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.
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