American Dryer Corp. AD-81 II User manual

010301DX/rar ADC Part No. 113311
For replacement parts, contact the reseller from which the dryer
was purchased or
American Dryer Corporation
88 Currant Road
Fall River MA 02720-4781
Telephone: [phone] / Fax: [phone]
E-mail: [email protected]
www.amdry.com
WARNING: For your safety the
information in this manual must be
followed to minimize the risk of fire or
explosion or to prevent property damage,
personal injury or death.
Do not store or use gasoline or other flammable
vapor and liquids in the vicinity of this or any
other appliance.
WHAT DO YOU DO IF YOU SMELL GAS
*Do not try to light any appliance.
*Do not touch any electrical switch; do not use
any phone in your building.
*Clear the room, building or area of all
occupants.
*Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's
instructions.
*If you cannot reach your gas supplier, call the
fire department.
Installation and service must be performed by a
qualified installer, service agency or the gas
supplier.
AVERTISSEMENT: Assurez-vous de bien
suivre les instructions données dans cette
notice pour réduire au minimumle risque
d’incendie ou d’explosion pour ou éviter tout
dommage matériel, toute blessure ou la mort.
Ne pas entreposer ni utiliser d’essence ni
d’autres vapeurs ou liquides inflammables dans
le voisinagede cet appareil ou de tout autre
appareil.
QUE FAIRE SI VOUS SENTEZ UNE ODEUR
DE GAZ:
*Ne pas tenter d’allumer d’appareil.
*Ne touchez à aucun interrupteur. Ne pas
vous servir des téléphones se trouvant dans
le bâtiment où vous vous trouvez.
*Évacuez la pièce le bâtiment ou la zone.
*Appelez immédiatement votre fournisseur de
gaz depuis un voisin. Suivez les instructions
du fournisseur.
*Si vous ne pouvez rejoindre le fournisseur
de gaz appelez le service des incendies.
Línstallation et l’entretien doivent être assurés
par un installateur ou un service d’entretien
qualiifié ou par le fournisseur de gaz.
AD-81 II
(Gas/Steam Models)
Installation Manual

Retain This Manual In A Safe Place For Future Reference
American Dryer Corporation products embody advanced concepts in engineering, design, and safety. If this product is
properly maintained, it will provide many years of safe, efficient, and trouble-free operation.
ONLY qualified technicians should service this equipment.
OBSERVEALLSAFETYPRECAUTIONS displayed on the equipment or specified in the installation manual included with
the dryer.
The following “FOR YOUR SAFETY” caution must be posted near the dryer in a prominent location.
AD-81 II
“IMPORTANT NOTE TO PURCHASER”
Information must beobtained from your local gas supplier on the instructions
to be followed if the user smells gas. These instructions must be posted in a
prominent location near the dryer.
FOR YOUR SAFETY
Do not store or use gasoline or
other flammable vapors or
liquids in the vicinity of this or
any other appliance.
POUR VOTRE SÉCURITÉ
Ne pas entreposer ni utiliser d’essence
ni d’autres vapeurs ou liquides
inflammables dans le voisinage de cet
appareil ou de yout autre appareil.
We have tried to make this manual as complete as possible and hope you will find it useful. ADC reserves the right to make
changes from time to time, without notice or obligation, in prices, specifications, colors, and material, and to change or
discontinue models. The illustrations included in this manual may not depict your particular dryer exactly.
Important
For your convenience, log the following information:
DATE OF PURCHASE________________________________ MODELNO. __________________________________________
RESELLER’S NAME ________________________________________________________________________________________
Serial Number(s) ________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
Replacement parts can be obtained from your reseller or theADCfactory. When orderingreplacement partsfromthefactory,
you can FAX your order to ADC at [phone] or telephone your order directly to the ADC Parts Department at (508)
678-9000. Please specify the dryer model number andserialnumberin addition to the description andpart number,sothat
your order is processed accurately and promptly.

IMPORTANT
YOU MUST DISCONNECT ANDLOCKOUTTHEELECTRICSUPPLY ANDTHEGAS
SUPPLY OR THE STEAM SUPPLY BEFORE ANY COVERS OR GUARDS ARE
REMOVED FROM THE MACHINE TO ALLOW ACCESS FOR CLEANING,
ADJUSTING, INSTALLATION, OR TESTING OF ANY EQUIPMENT PER OSHA
(Occupational Safety and Health Administration)STANDARDS.
WARNING
CHILDREN SHOULD NOTBEALLOWED TO PLAY ON OR NEAR THE DRYER(S).
CHILDREN SHOULD BESUPERVISED IF NEAR DRYERS IN OPERATION.
CAUTION
DRYERS SHOULD NEVER BE LEFT UNATTENDED WHILE IN OPERATION.
FOR YOUR SAFETY
DO NOTDRY MOP HEADS IN THE DRYER.
DO NOT USE DRYER IN THE PRESENCE OF DRY CLEANING FUMES.
WARNING
UNDER NO CIRCUMSTANCES should the dryer door switch, lint drawer switch, or
the heat circuit safety devices ever be disabled.
“Caution: Label all wires prior to
disconnection when servicing controls. Wiring
errors can cause improper operation.”
«Attention: Lordesopérationsd’entretien
des commandes étiqueter tous fils avant
de les déconnecter. Toute erreur de
câblage peut étre une source de danger et
de panne.»

WARNING
The dryer must never be operated with any of the back guards, outer tops, or service
panels removed. PERSONAL INJURY OR FIRE COULD RESULT.
IMPORTANT
PLEASE OBSERVEALLSAFETY PRECAUTIONS displayedon the equipmentand/or
specified in the installation manual included with the dryer.
WARNING
DRYER MUST NEVER BE OPERATED WITHOUT THE LINT FILTER/SCREEN IN
PLACE, EVEN IF AN EXTERNAL LINT COLLECTION SYSTEM IS USED.
Dryersmust not beinstalled or stored in an area where itwillbe exposedto waterorweather.
The wiring diagram for the dryer is located in the front electrical control box area.

Table of Contents
SECTION I
IMPORTANT INFORMATION..........................................................................3
A. Receiving and Handling ............................................................................................................... 3
B. Safety Precautions ...................................................................................................................... 4
SECTION II
SPECIFICATIONS/COMPONENT IDENTIFICATION..................................6
A. Specifications ............................................................................................................................. 6
B. Component Identification ............................................................................................................ 8
SECTION III
INSTALLATION PROCEDURES ....................................................................10
A. Location Requirements ............................................................................................................. 10
B. Unpacking/Setting Up ................................................................................................................11
C. Dryer Enclosure Requirements .................................................................................................. 12
D. Fresh Air Supply Requirements ................................................................................................. 13
E. Exhaust Requirements ............................................................................................................... 14
F. Electrical Information ................................................................................................................ 20
G. Gas Information........................................................................................................................ 23
H. Steam Information .................................................................................................................... 27
I. Preparation For Operation/Start-Up ......................................................................................... 31
J. Preoperational Tests ................................................................................................................. 32
K. Preoperational Instructions ........................................................................................................ 34
L. Shut Down Instructions ............................................................................................................. 34
SECTION IV
SERVICE/PARTS INFORMATION .................................................................35
A. Service ..................................................................................................................................... 35
B. Parts ........................................................................................................................................ 35
SECTION V
WARRANTY INFORMATION .........................................................................36
A. Returning Warranty Cards......................................................................................................... 36
B. Warranty .................................................................................................................................. 36
C. Returning Warranty Parts .......................................................................................................... 36

SECTION VI
ROUTINE MAINTENANCE ............................................................................38
A. Cleaning ................................................................................................................................... 38
B. Adjustments ............................................................................................................................. 39
C. Lubrication ............................................................................................................................... 40
D. Lint Drawer Removal................................................................................................................ 40
SECTION VII
TROUBLESHOOTING.....................................................................................41
SECTION VIII
DATA LABEL.....................................................................................................48
A. Data Label ............................................................................................................................... 48
SECTION IX
PROCEDURE FOR FUNCTIONAL CHECK OF REPLACEMENT
COMPONENTS ................................................................................................50
SECTION X
BURNER AND BASKET (TUMBLER)/LINT CHAMBER
MANUAL RESET HI-LIMIT INSTRUCTIONS ..............................................53

3
SECTION I
IMPORTANT INFORMATION
A. RECEIVING AND HANDLING
The dryer is shipped in a protective stretch wrap cover with protective cardboard corners and top cover
(or optional box) as a means of preventing damage in transit. Upon delivery, the dryer and/or protective packaging,
and wooden skid should be visually inspected for shipping damage. If any damage whatsoever is noticed,
inspect further before delivering carrier leaves.
Dryers damaged in shipment:
1. ALL dryers should be inspected upon receipt and before they are signed for.
2. If there is suspected damage or actual damage, the trucker’s receipt should be so noted.
3. If the dryer is damaged beyond repair, it should be refused. Those dryers which were not damaged in a
damaged shipment should be accepted, but the number received and the number refused must be noted
on the receipt.
4. If you determine that the dryer was damaged after the trucker has left your location, you should call the
delivering carrier’s freight terminal immediately and file a claim. The freight company considers this
concealed damage. This type of freight claim is very difficult to get paid and becomes extremely difficult
when more than a day or two passes after the freight was delivered. It is your responsibility to file freight
claims. Dryers/parts damaged in transit cannot be claimed under warranty.
5. Freight claims are the responsibility of the consignee, and ALL claims must be filed at the receiving end.
ADC assumes no responsibility for freight claims or damages.
6. If you need assistance in handling the situation, please contact the ADC Traffic Manager at (508)
678-9000.
IMPORTANT: The dryer must be transported and handled in an upright position at ALL times.

4
B. SAFETY PRECAUTIONS
WARNING: For your safety, the information in this manual must be followed to minimize the risk of
fire or explosion or to prevent property damage, personal injury, or loss of life.
WARNING: The dryer must never be operated with any of the back guards, outer tops, or
service panels removed. PERSONAL INJURY OR FIRE COULD RESULT.
1. DO NOT store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other
appliance.
2. Purchaser/user should consult the local gas supplier for proper instructions to be followed in the event the
user smells gas. The instructions should be posted in a prominent location.
3. WHAT TO DO IF YOU SMELL GAS...
a. DO NOT try to light any appliance.
b. DO NOT touch any electrical switch.
c. DO NOT use any phone in your building.
d. Clear the room, building, or area of ALLoccupants.
e. Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
f. If you cannot reach your gas supplier, call the fire department.
4. Installation and service must be performed by a qualified installer, service agency, or gas supplier.
5. Dryer(s) must be exhausted to the outdoors.
6. Although ADC produces a very versatile dryer, there are some articles that, due to fabric composition or
cleaning method, should not be dried in it.
WARNING: Dry only water washed fabrics. DO NOT dry articles spotted or washed in dry
cleaning solvents, a combustible detergent, or “all purpose” cleaner.
EXPLOSION COULD RESULT.
WARNING: DO NOT dry rags or articles coated or contaminated with gasoline, kerosene, oil, paint,
or wax.
EXPLOSION COULD RESULT.
WARNING: DO NOT dry mop heads. Contamination by wax or flammable solvents will create a
fire hazard.
WARNING: DO NOT use heat for drying articles that contain plastic, foam, sponge rubber, or
similarly textured rubberlike materials. Drying in a heated basket (tumbler) may damage
plastics or rubber and may be a fire hazard.

5
7. A program should be established for the inspection and cleaning of lint in the burner area, exhaust
ductwork, and area around the back of the dryer. The frequency of inspection and cleaning can best be
determined from experience at each location.
WARNING: The collection of lint in the burner area and exhaust ductwork can create a potential fire
hazard.
8. For personal safety, the dryer must be electrically grounded in accordance with local codes and/or the
National Electrical Code ANSI/NFPA NO. 70-LATEST EDITION, or in Canada, the Canadian Electrical
Codes Parts 1 & 2 CSA C22.1-1990 or LATEST EDITION.
NOTE: Failure to do so will VOID THE WARRANTY.
9. UNDER NO CIRCUMSTANCES should the dryer door switch, lint drawer switch, or the heat circuit
safety devices ever be disabled.
WARNING: PERSONALINJURY OR FIRE COULD RESULT.
10. This dryer is not to be used in the presence of dry cleaning solvents or fumes.
11. Remove articles from the dryer as soon as the drying cycle has been completed.
WARNING: Articles left in the dryer after the drying and cooling cycles have been completed can
create a fire hazard.
12. DO NOT operate steam dryers with more than 125 PSI (8.62 bars) steam pressure. Excessive steam
pressure can damage steam coil and/or harm personnel.
13. Replace leaking flexible steam hoses or other steam fixtures immediately. DO NOT operate dryer with
leaking flexible hoses. PERSONAL INJURY MAY RESULT.
14. READ AND FOLLOWALLCAUTIONAND DIRECTION LABELS ATTACHED TO DRYER.
15. For safety, proper operation, and optimum performance, the dryer must not be operated with a load less
then sixty-six percent (66%), 53 lbs (24.04 kg) of its rated capacity.
IMPORTANT: YOU MUST DISCONNECT AND LOCKOUT THE ELECTRIC SUPPLY
AND THE GAS SUPPLY OR THE STEAM SUPPLY BEFORE ANY
COVERS OR GUARDS ARE REMOVED FROM THE MACHINE TO
ALLOW ACCESS FOR CLEANING, ADJUSTING, INSTALLATION, OR
TESTING OF ANY EQUIPMENT PER OSHA (Occupational Safety and Health
Administration) STANDARDS.

6
SECTION II
SPECIFICATIONS/COMPONENT IDENTIFICATION
A. SPECIFICATIONS
*Refer to Electrical Service Specifications chart on page 21.
IMPORTANT: Steam dryers must be provided with a clean, dry, and regulated 80 PSI +/- 10 PSI
(5.51 bars +/- 0.68 bars) air supply. Air volume requirement is 0.75 cfh (cubic feet
per hour) - 0.02 cmh (cubic meters per hour).
NOTE: ADCreserves the right to make changes in specifications at any time without notice or
obligation.
BASKET (TUMBLER) DIAMETER 37” 94 cm
BASKET (TUMBLER) DEPTH 36” 91.5 cm
BASKET (TUMBLER) MOTOR 1/2 HP 0.373 kw
BLOWER MOTOR 3 HP 2.238 kw
DOOR OPENING (DIAMETER) 21-1/2” 54.61 cm
BASKET (TUMBLER) VOLUME 22.4 cu. ft. 0.634 cu. m.
DRYERS PER 20'/40' CONTAINER 10/20
DRYERS PER 48'/53' TRUCK 24/26
VOLTAGE AVAILABLE* 208-460v 3ø 50/60 Hz
APPROX. WEIGHT (UNCRATED) 756 lbs 342.9 kg
APPROX. WEIGHT (CRATED) 806 lbs 365.6 kg
HEAT INPUT 270,000 btu/hr 68,040 kcal/hr
AIRFLOW 1,700 cfm 48.14 cmm
INLET PIPE SIZE 1” F.P.T.
VOLTAGE AVAILABLE* 208-460v 3ø 50/60 Hz
APPROX. WEIGHT (UNCRATED) 789 lbs 357.9 kg
APPROX. WEIGHT (CRATED) 839 lbs 380.6 kg
AIRFLOW 1,700 cfm 48.14 cmm
AIR VOLUME 0.75 cfh 0.02 cmh
AIR CONNECTION 1/8” F.P.T.
STEAM CONSUMPTION BOILER HP
NORMAL LOAD
375 lbs/hr 170.5 kg/hr 11
OPERATING STEAM PRESSURE STEAM SUPPLY STEAM RETURN
125 PSI max 8.6bars 1” N.P.T. 1” N.P.T.
Shaded areas are stated in metric equivalents
GasSteam

7
Specifications
ADS-81 II
ADG-81 II
NOTE: ADCreserves the right to make changes in specifications at any time without notice or
obligation.

8
B. COMPONENT IDENTIFICATION
1. Dryer Front View
Illus. No. Description
1Microprocessor Control / Keyboard (touch pad) Panel Assembly (controls)
2Control (top access) Door Assembly
3Main Door Assembly
4Lint Compartment Area (located behind front panel)
5Lint Drawer
6Data Label and Installation Label (data label that is affixed to the left side panel area behind the
top control [access] door).

9
2. Dryer Rear View
NOTE:1/8-inch compressed air supply inlet (for steam models only) is located behind the electric
service relay box...Not illustrated.
Illus. No. Description
1Heating Unit
21/8” Compressed Air Supply Inlet
(behind electric service relay box for steam units only)
3* Electric Service Relay Box
4Basket (tumbler) Bearing Mount Assembly
5Idler Bearing Mount Assembly
6Blower Motor Assembly
7Leveling Leg (rear)
8Basket (tumbler) Drive Motor Assembly (reversing models only)
9Dryer Exhaust
* Electric service connections for gas and steam models are made in this box.

10
SECTION III
INSTALLATION PROCEDURES
Installation should be performed by competent technicians in accordance with local and state codes. In the
absence of these codes, the installation must conform toapplicableAmerican NationalStandards: ANSI Z223.1-
LATEST EDITION (National Fuel Gas Code) or ANSI/NFPA NO. 70-LATEST EDITION (National Electrical
Code) or in Canada, the installation must conform to applicable Canadian Standards: CAN/CGA-B149.1-M91
(Natural Gas) or CAN/CGA-B149.2-M91 (Liquid Propane [L.P.] Gas) or LATEST EDITION (for General
Installation and Gas Plumbing) or Canadian Electrical Codes Parts 1 & 2 CSA C22.1-1990 or LATEST EDITION
(for Electrical Connections).
A. LOCATION REQUIREMENTS
Before installing the dryer, be sure the location conforms to local codes and ordinances. In the absence of such
codesorordinances the locationmust conform withtheNationalFuelGasCodeANSI.Z223.1LATESTEDITION,
or in Canada, the installation must conform to applicable Canadian Standards: CAN/CGA-B149.1-M91 (Natural
Gas) or CAN/CGA-B149.2-M91 (L.P. Gas) or LATEST EDITION (for General Installation and Gas Plumbing).
1. The dryer must be installed on a sound level floor capable of supporting its weight. Carpeting must be
removed from the floor area that the dryer is to rest on.
IMPORTANT: “The dryer must be installed on noncombustible floors only.”
2. The dryer must not be installed or stored in an area where it will be exposed to water and/or weather.
3. Provisions for adequate air supply must be provided as noted in this manual (refer to Fresh Air Supply
Requirements in Section D).
4.Clearance provisions must be made from combustible construction as noted in this manual (refer to Dryer
Enclosure Requirements in Section C).
5. Provisions must be made for adequate clearances for servicing and for operation as noted in this manual
(refer to Dryer Enclosure Requirements in Section C).
6. Dryer must be exhausted to the outdoors as noted in this manual (refer to Exhaust Requirements in
Section E).
7.Dryer must be located in an area where correct exhaust venting can be achieved as noted in this manual
(refer to Exhaust Requirements in Section E).
IMPORTANT: Dryer should be located where a minimum amount of exhaust duct will be necessary.
8. The dryer must be installed with a proper exhaust duct connection to the outside.
9. The dryer must be installed with provisions for adequate combustion and make-up air supply.

11
B. UNPACKING/SETTING UP
1. Inside the basket (tumbler) of this dryer is an exhaust
transition piece that must be installed on the outlet of
the exhaust before any further venting is connected. To
do this, follow the procedures listed below:
a. Remove the exhaust transition piece from the basket
(tumbler) and place it on the exhaust outlet.
b. Using the screws provided, secure the exhaust
transition piece to the dryer.
NOTE:It is recommendedthat this joint be taped
as well as ALL other duct joints to prevent
moisture and lint from escaping into the
building.
2. Leveling Dryer
The dryer is equipped with four (4) leveling legs, one (1)
at each corner of the dryer base. Two (2) are located in
the rear of the dryer base, and two (2) are located in the
lint chamber. To increase bearing life and improve
efficiency, the dryershould be tilted slightly to the rear.
WARNING
Anexhaustducttransitionpieceisshippedinsideofthedryer’s
tumbler and MUST be installed on the dryer’s
exhaust duct, with the hardware provided, BEFORE
location venting is connected to the dryer.
THIS EXHAUST DUCT TRANSITION PIECE
MUST BE INSTALLED FIRST!
Failure to observe this installation requirement may result in
damage to the dryer, create aFIRE HAZARD and will VOID
the manufacturer’s warranty.
012999JEV-GS/cj P/N: 114092
CAUTION: This dryer produces combustible lint and must be exhausted to the outdoors. Every 6
months, inspect the exhaust ducting and remove any lint build up.

12
C. DRYER ENCLOSURE REQUIREMENTS
Bulkheads and partitions should be made of noncombustible materials and must be located a minimum of
12-inches (30.48 cm), 18-inches (45.72 cm) or more is recommended for ease of installation, maintenance, and
service, above the dryer outer top, except along the front of the dryer which may be partially closed in if desired.
The clearance between the bulkhead header and the dryer must bea minimum of 4-inches (10.16 cm) and must
not extend more than 4-inches (10.16 cm) to the rear of the front. The bulkhead facing must not be closed in
ALL the way to the top of the dryer. A 1-inch (2.54 cm) clearance is required.
NOTE: Allowances must be made for opening the control door.
Dryers may be positioned sidewall to sidewall. However, a 1/16” (1.5875 mm) minimum allowance must be
made for opening and closing of the control and lint doors. It is suggested that the dryer be positioned about 2 feet
(0.61 meters) away from the nearest obstruction for ease of installation, maintenance, and service (to be measured
from the back guard). Refer to the illustration above for details.
NOTE: Air considerations are important for proper and efficient operation.
IMPORTANT: Even though a minimum of only 12-inches (30.48 cm) is required, 18-inches (45.72
cm) or more is suggested, especially in the cases where sprinkler heads are over the
dryers. The additional clearance is also advantageous for ease of installation and
service.

13
IMPORTANT: When fire sprinkler systems are located above the dryers, a minimum of 18-inches
(45.72 cm) above the dryer console (module) is required. Dryers may be positioned
sidewall to sidewall, however, a 1/16” (1.5875 mm) minimum allowance is required
between dryers (or wall) for ease of installation and maintenance. Allowances must
be made for the opening and closing of the control door and the lint door.
D. FRESH AIR SUPPLYREQUIREMENTS
When the dryer is operating, it draws in room air, heats it, passes this air through the basket (tumbler), and
exhausts it out of the building. Therefore, the room airmust 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.
Air supply (make-up air) must be given careful consideration to assure proper performance of each dryer. An
unrestricted source of air is necessary for each dryer. An airflow of 1,700 cfm (cubic feet per minute) (48.14
cmm [cubic meters per minute]) must be supplied to each dryer. As a general rule, an unrestricted air entrance
from the outdoors (atmosphere) of a minimum of 2-1/2 square feet (0.23 square meters) is required for each
dryer. The dryer must be installed with provisions for adequate combustion and make-up air supply.
To compensate for the use of registers or louvers used over the openings, this make-up airmust beincreased by
approximately thirty-three percent (33%). Make-up air openings should not be located in an area directly near
where exhaust vents exit the building.

14
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.
EXAMPLE: For a bank of four (4) dryers, two (2) openings measuring 2 feet by 2-1/2 feet (0.61 meters
by 0.76 meters) (10 square feet [0.93 square meters]) is acceptable.
Allowances must be made for remote or constricting passageways or where dryers are located at excessive
altitudes or predominantly low pressure areas.
IMPORTANT: Make-up air must be provided from a source 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.
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-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: DRYER MUST BE EXHAUSTED TO THE OUTDOORS.
CAUTION: IMPROPERLY SIZED OR INSTALLED EXHAUSTDUCTWORKCAN
CREATE APOTENTIALFIREHAZARD.
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 the 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 outletmust not exceed 15 feet (4.57 meters). The shape of the ductwork is not critical
so long as the minimum cross section 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 elbowsshould 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 section area of the ductwork must be increased in proportion to the number of
elbows added.

15
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 jointsmust 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 at each basket (tumbler) exhaust
duct area must be no less than 0 and must not exceed 0.3 inches (0.74 mb) of water
column (W.C.).
IMPORTANT: Minimum ductwork diameter is 14-inches (35.56 cm).
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.
a. Outside Ductwork Protection
1) To protect the outside end of the horizontal ductwork from the weather, a 90º elbow bent downward
should be installed where the exhaust exits the building. If the ductwork travels vertically up
through the roof, it should be protected from the weather by using a 180º turn to point the opening
downward. In either case, allow at least twice the diameter of the duct opening and the nearest
obstruction.
IMPORTANT: DO NOT use screens, louvers, or caps on the outside opening of the exhaust
ductwork.

16
2. Single Dryer Venting
Where possible, it is suggested to provide a separate exhaust duct for each dryer. The exhaust ductshould
be laid out in such a way that the ductwork travels as directly as possible to the outdoors with as few turns
as possible. It is suggested that the use of 90° turns in the ducting be avoided; use 30° and/or 45° angles
instead. The shape of the exhaust ductwork is not critical so long as the minimum cross section area is
provided.
IMPORTANT: Minimum duct size for a dryer is 14-inches (35.56 cm) for a round duct or
12-1/2” x 12-1/2” (31.75 cm x 31.75 cm) for a square duct. THE DUCT SIZE
MUST NOT BE REDUCED ANYWHERE DOWNSTREAM OF THE
DRYER.
IMPORTANT: Exhaust back pressure measured by a manometer at each basket (tumbler) exhaust
duct area must be no less than 0 and must not exceed 0.3 inches (0.74 mb) of water
column (W.C.).
It is suggested that the ductwork from each dryer not exceed 15 feet (4.57 meters) with no more than two
(2) elbows (excluding dryer connections and outside exhaust outlets). If the ductwork exceeds 15 feet
(4.57 meters) or has numerous elbows, the cross section area of the ductwork must be increased in
proportion to the length and number of elbows in it. In calculating duct size, the cross section area of a
square or rectangular duct must be increased by twenty percent (20%) for each additional 15 feet (4.57
meters). The diameter of a round exhaust duct should be increased ten percent (10%) for each additional
15 feet (4.57 meters). Each 90º elbow is equivalent to an additional 30 feet (9.14 meters), and each 45º
elbow is equivalent to an additional 15 feet (4.57 meters).