12
American Dryer Corp.
113344 - 9
E. EXHAUST REQUIREMENTS
1. General Exhaust Ductwork Information
Exhaust ductwork
should be
designed and installed by a qualified professional. Improperly sized ductwork
will create excessive back pressure which results in slow drying, increased use of energy, overheating of
the dryer, and shut down of the burner by the airflow (sail) switches, burner hi-limits, or basket (tumbler)
hi-heat thermostats. The dryer
must be
installed with a proper exhaust duct connection to the outside.
CAUTION:
This dryer produces combustible lint and
must be
exhausted to the outdoors.
CAUTION: IMPROPERLY
SIZED
OR
INSTALLED
EXHAUST
DUCTWORK
CAN
CREATE
A
POTENTIAL
FIRE
HAZARD.
The ductwork
should be
laid out in such a way that the ductwork travels as directly as possible to the
outdoors with as few turns as possible. Single or independent dryer venting is recommended.
When single dryer venting is used, the length of ductwork from the dryer to the outside exhaust outlet
must
not
exceed
15 feet (4.57 meters). The minimum diameter of this ductwork
must be
at least 14-inches
(35.56 cm). In the case of multiple (common) dryer venting, the distance from the last dryer to the outside
exhaust outlet
must not
exceed
15 feet (4.57 meters). The shape of the ductwork is not critical as long
as the minimum cross-sectional area is provided. It is suggested that the use of 90° turns be avoided; use
30° and/or 45° angles instead. The radius of the elbows
should preferably be
1-1/2 times the diameter of
the duct. Including basket (tumbler) and dryer elbow connections or elbows used for outside protection
from the weather, no more than two (2) elbows
should be
used in the exhaust duct run. If more than two
(2) elbows are used, the cross-sectional area of the ductwork
must be
increased.
ALL
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. Inspection doors
should be
installed at strategic points in the exhaust ductwork for periodic
inspection and cleaning of lint from the ductwork.
IMPORTANT:
Exhaust back pressure measured by a manometer in the exhaust duct
must be
no less
than 0 and
must not
exceed
0.3 inches (0.74 mb) of water column (W.C.).
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.
IMPORTANT: It is recommended
that exhaust or booster fans not be used in the exhaust ductwork
system.
NOTE:
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 [0.5 mm]) thick.”
