American Dryer Corp. ML-170 - Manual (Page 13)

113360 - 8 www.amdry.com 13
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
shutdown of the burner by the airflow (sail) switches, burner hi-limits, or 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.
NOTE: When dryers are exhausted into a multiple (common) exhaust line, each dryer must be supplied with a
back draft damper.
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 ductwork from the dryer to the outside exhaust outlet should not exceed 20
feet (6.09 meters). In the case of multiple (common) dryer venting, the distance from the last dryer to the outside
exhaust outlet should not exceed 20 feet (6.09 meters). The shape of the ductwork is not so critical as long as the
minimum cross-sectional area is provided. It is suggested that the use of 90º turns be avoided; use 30º and/or 45º
bends/angles instead. The radius of the elbows should preferably be 1-1/2 times the diameter of the duct.
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.
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.”
IMPORTANT: It is recommended that exhaust or booster fans not be used in the exhaust ductwork system.