American Dryer Corp. T20 - Manual (Page 11)

113428-9 Telephone 01422 822282 11
Exhaust Requirements ________________
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, and shutdown of the burner by the
airflow (sail) switch, burner hi-limits, or lint chamber hi-limit
protector thermostat. 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.
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. There should be a minimum 6-inch (15.24 cm)
clearance between the back guard and the first bend in the
ductwork for ease of servicing. Single or independent dryer
venting is recommended. It is suggested that the use of 90°
turns be avoided; use 30° and/or 45° 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, overlap the duct
being connected. All ductwork joints must be taped to prevent
moisture and lint from escaping into the building. Back draft
dampers must be installed in all commonly ducted systems.
Inspection doors should be installed at strategic points in the
exhaust ductwork for periodic inspection and cleaning of lint
from the ductwork.
Important
It is recommended that exhaust or booster fans not
be used in the exhaust ductwork system.
Exhaust back pressure measured by a manometer/
magnehelic in the exhaust duct must be no less than 0 and
must not exceed 0.6 in WC (1.48 mb).
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.
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 [0.50 mm]) thick.”
The ductwork for this appliance must be suitable for the
appliance category in accordance with national installation
regulations of the country of destination.
!
!
!
!
Fresh Air Supply Requirements _______
When the dryer is operating, it draws in room air, heats it,
passes this air through the tumbler, and exhausts it out of the
building. Therefore, the room air must be continually
replenished from the outdoors. If the make-up air is
inadequate, drying time and drying efficiency will be adversely
affected. Ignition problems and sail switch “fluttering” problems
may result, as well as premature motor failure from
overheating. The dryer must be installed with provisions for
adequate combustion and make-up air supply.
Air supply (make-up air) must be given careful consideration
to ensure proper performance of each dryer. As a general
rule, an unrestricted air entrance from the outdoors of 110 inch
2
(710 cm 2 ) is required for each T30 stack and 80 inch 2 (516
cm 2 ) for each T20 stack. (Based on 1 inch 2 [6.5 cm 2 ] per 1,000
Btu [252 kcal].)
It is not necessary to have a separate make-up air opening for
each dryer. Common make-up air openings are acceptable.
However, they must be set up in such a manner that the
make-up air is distributed equally to all the dryers.
A = 14-inches (35.56 cm) B = 16-inches (40.64 cm)
EXAMPLE: For a bank of 4 T30 stack dryers, 2 unrestricted
openings measuring 14-inches by 16-inches (35.56 cm by
40.64 cm) are acceptable.
To compensate for the use of registers or louvers used over
the openings, this area must be increased by approximately
33%. Make-up air openings should not be located in an area
directly near where exhaust vents exit the building.
Allowances must be made for remote or constricting
passageways or where dryers are located at high altitudes or
predominantly low pressure areas.
Important
Make-up air must be free of dry cleaning solvent
fumes. Make-up air that is contaminated by dry
cleaning solvent fumes will result in irreparable damage to
the motors and other dryer components.
Note
Component failure due to dry cleaning solvent
fumes will void the warranty.
!