15
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 basket (tumbler)
hi-limit 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
.
IMPORTANT: It
is
recommended
that exhaust or booster fans not be used in the exhaust ductwork
system.
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.
HORIZONTAL VENTING:
When single dryer venting is used, the length of the ductwork from the dryer to the outside exhaust outlet
must not exceed
15 feet (4.6 meters). The minimum diameter of this ductwork
must be
at least
10-inches (25.4 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 (4.6 meters). The shape of the ductwork is not critical so
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)/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.
VERTICAL VENTING:
When single dryer venting is used, the length of the ductwork from the dryer to the outside exhaust outlet
must not exceed
20 feet (6.1 meters). The minimum diameter of this ductwork
must be
at least
12-inches (30.48 cm). In the case of multiple (common) dryer venting, the distance from the last dryer to
the outside exhaust outlet
must not exceed
20 feet (6.1 meters). The shape of the ductwork is not critical
so 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 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.
