American Dryer Corp. ML-122 User manual

ML-122 Installation Manual
Phase 7 / Non-Coin
AmericanDryerCorporation
88Currant Road
FallRiverMA02720-4781
Telephone:[phone] / Fax:[phone]
e-mail: [e-mail]
www.amdry.com
WARNING: Foryoursafetytheinformationin
thismanual mustbe followedto minimizethe
riskof fireor explosionor toprevent property
damage,personalinjury or death.
— Donot storeoruse gasolineor other flammable
vapors and liquids in the vicinity of this or any
otherappliance.
— WHATTO DO IFYOU SMELLGAS:
• Donottryto lightany appliance.
• Donottouch anyelectricalswitch;do not
useanyphoneinyourbuilding.
• Cleartheroom, building orareaofall
occupants.
• Immediatelycallyourgassupplierfroma
neighbor’sphone. Followthe gas supplier’s
instructions.
• Ifyoucannotreach yourgas supplier,call
thefiredepartment.
— Installationand servicemustbe performedby a
qualified installer, service agency or the gas
supplier.
AVERTISSEMENT: Assurez-vous de bien
suivrelesinstructionsdonnéesdanscettenotice
pourréduire auminimumle risqued’incendie
ou d’explosion ou pour éviter tout dommage
matériel,touteblessureou lamort.
— Ne pas entreposer ni utiliser d’essence ni
d’autres vapeurs ou liquides inflammables à
proximité de cet appareil ou de tout autre
appareil.
— QUEFAIRESIVOUSSENTEZUNEODEUR
DEGAZ:
• Nepastenter d’allumerd’appareils.
• Netouchez àaucun interrupteur. Ne pas
vousservirdes téléphonessetrouvant dans
lebâtiment.
• Évacuezlapièce,le bâtimentoulazone.
• Appelezimmédiatementvotrefournisseur
degazdepuisunvoisin. Suivezles
instructionsdufournisseur.
• Sivousnepouvezrejoindrelefournisseur
degaz,appelez leservicedes incendies.
— L’installationetl’entretiendoiventêtreassuréspar
uninstallateurou unserviced’entretienqualifié
ouparle fournisseurdegaz.
ADCPartNo.113363

Retain This Manual In ASafe 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.
OBSERVE ALL SAFETY PRECAUTIONS 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.
“IMPORTANTNOTETOPURCHASER”
Informationmustbeobtainedfromyourlocalgassupplierontheinstructions
tobefollowed iftheusersmells gas. Theseinstructionsmustbeposted ina
prominentlocationnearthedryer.
FORYOUR SAFETY
Donot storeor usegasoline or
otherflammablevaporsand
liquidsinthevicinityofthisor
anyotherappliance.
POURVOTRESÉCURITÉ
Nepas entreposer niutiliserd’essence
nid’autresvapeursouliquides
inflammablesàproximitédecet
appareilou detoutautre 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 OFPURCHASE________________________________ MODELNO. __________________________________________
RESELLER’SNAME ________________________________________________________________________________________
Serial Number(s) ________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
Replacement parts can be obtained from your reseller or the ADCfactory. When ordering replacement parts from the factory,
you can FAX your order to ADC at [phone] or telephone your order directly to the ADC Parts Department at (508)
678-9000. Pleasespecify the dryermodel numberand serial numberin additionto the descriptionandpart number,sothat
your order is processed accurately and promptly.
ML-122

IMPORTANT
YOUMUSTDISCONNECTANDLOCKOUTTHEELECTRICSUPPLYANDTHEGAS
SUPPLY OR THE STEAM SUPPLY BEFORE ANY COVERS OR GUARDS ARE
REMOVED FROM THE MACHINE TO ALLOW ACCESS FOR CLEANING,
ADJUSTING, INSTALLATION, OR TESTING OFANY EQUIPMENT PER OSHA
(OccupationalSafetyand HealthAdministration)STANDARDS.
WARNING
CHILDRENSHOULD NOTBEALLOWEDTOPLAYONORNEARTHEDRYER(S).
CHILDRENSHOULDBESUPERVISEDIFNEARDRYERSINOPERATION.
CAUTION
DRYERSSHOULDNEVERBELEFTUNATTENDEDWHILEINOPERATION.
FORYOURSAFETY
DONOTDRYMOPHEADSINTHEDRYER.
DONOTUSEDRYERINTHEPRESENCEOFDRYCLEANINGFUMES.
WARNING
UNDERNOCIRCUMSTANCESshould the dryerdoorswitch,thelintdrawerswitch,
or the heat safety circuit ever be disabled.
“Caution: Label all wires prior to
disconnection when servicing controls. Wiring
errors can cause improper operation.”
«Attention: Au moment de l’entretien des
commandes,étiqueteztous les filsavantde
les débrancher. Des erreurs de câblage
peuvent entraîner un fonctionnement
inadéquatetdangereux.»

WARNING
The dryer must never be operated with any of the back guards, outer tops, or service
panelsremoved. PERSONALINJURYORFIRECOULDRESULT.
IMPORTANT
PLEASEOBSERVEALLSAFETYPRECAUTIONSdisplayedontheequipmentand/or
specified in the installation manual included with the dryer.
WARNING
DRYERMUSTNEVERBEOPERATEDWITHOUTTHELINTFILTER/SCREENIN
PLACE,EVENIFANEXTERNALLINTCOLLECTIONSYSTEMISUSED.
Dryers mustnotbeinstalledorstoredin an area where it willbeexposed to waterorweather.
The wiring diagram for the dryer is located in the front electrical control box area.
IMPORTANT
Dryer must be installed in a location/environment, which the ambient temperature
remains between 40° F (4.44° C) and 130° F (54.44° C).

SECTIONI
SAFETYPRECAUTIONS ........................................................................................................2
SECTIONII
SPECIFICATIONS/COMPONENTIDENTIFICATION .......................................................4
A. Specifications.......................................................................................................................................... 4
B. ComponentIdentification........................................................................................................................ 6
SECTIONIII
INSTALLATIONPROCEDURES ...........................................................................................8
A. Location Requirements........................................................................................................................... 8
B. Unpacking/Setting Up............................................................................................................................. 9
C. Dryer Enclosure Requirements ............................................................................................................ 11
D. FreshAir Supply Requirements ............................................................................................................ 11
E. Exhaust Requirements.......................................................................................................................... 12
F. Electrical Information ........................................................................................................................... 17
G. Gas Information .................................................................................................................................... 19
H. Steam Information ................................................................................................................................ 23
I. Water Information ................................................................................................................................ 26
J. Preparation for Operation/Start-Up...................................................................................................... 29
K. Preoperational Tests ............................................................................................................................. 30
L. Preoperational Instructions ................................................................................................................... 31
M. Compressed Air Requirements ............................................................................................................. 33
N. Shutdown Instructions .......................................................................................................................... 34
SECTIONIV
SERVICE/PARTSINFORMATION ......................................................................................35
A. Service .................................................................................................................................................. 35
B. Parts...................................................................................................................................................... 35
SECTIONV
WARRANTYINFORMATION ..............................................................................................36
A. Returning Warranty Cards ................................................................................................................... 36
B. Warranty ............................................................................................................................................... 36
C. Returning Warranty Parts..................................................................................................................... 36
SECTIONVI
ROUTINEMAINTENANCE .................................................................................................38
A. Cleaning ................................................................................................................................................ 38
B. Adjustments .......................................................................................................................................... 39
C. Lubrication ............................................................................................................................................ 39
SECTIONVII
MANUALRESETHI-LIMITINSTRUCTIONS ...................................................................40
A. Phase 7 ................................................................................................................................................. 40
B. DualTimer ............................................................................................................................................ 40
SECTIONVIII
DATALABELINFORMATION ............................................................................................41
SECTIONIX
PROCEDUREFORFUNCTIONALCHECKOFREPLACEMENTCOMPONENTS .....42
Table of Contents

2American Dryer Corp. 113363-6
SECTIONI
SAFETYPRECAUTIONS
WARNING: Foryour safety, the information in this manual mustbefollowedto minimizetherisk of
fireor explosionor toprevent propertydamage, personalinjury, orloss of life.
WARNING: The dryer must never beoperated 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 ALL occupants.
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
cleaningsolvents, acombustible detergent,or “allpurpose” cleaner.
EXPLOSIONCOULDRESULT.
WARNING: DO NOT dry rags or articles coated or contaminated with gasoline, kerosene, oil,paint,
or wax. EXPLOSION COULDRESULT.
WARNING: DO NOT dry mop heads. Contamination by wax or flammable solvents will create a
firehazard.
WARNING: DONOT 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.

113363-6 www.amdry.com 3
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: Thecollection of lintin theburner areaand exhaustductwork cancreate a potentialfire
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 electrically ground the dryer properly willVOIDTHEWARRANTY.
9. UNDER NO CIRCUMSTANCES should the dryer door switch, the lint drawer switch, or the heat
safety circuit ever be disabled.
WARNING: PERSONALINJURYOR FIRE COULD RESULTSHOULDTHE DRYER
DOOR SWITCH,THELINT DRAWER SWITCH, ORTHEHEATSAFETY
CIRCUIT EVER BE DISABLED.
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: Articlesleft in thedryer afterthe dryingand coolingcycles have been completed can
createa firehazard.
12. READ AND FOLLOW ALL CAUTION AND DIRECTION LABELS ATTACHED TO THE DRYER.
13. For safety, proper operation, and optimum performance, the dryer must not be operated with a load less
than sixty-six percent (66%), 79 pounds (35.83 kg) of its rated capacity.
WARNING: YOUMUSTDISCONNECTANDLOCKOUTTHEELECTRICSUPPLYAND
THEGAS SUPPLYOR THESTEAM SUPPLYBEFOREANYCOVERSOR
GUARDSAREREMOVEDFROMTHEMACHINETOALLOWACCESS
FOR CLEANING,ADJUSTING,INSTALLATION,ORTESTINGOFANY
EQUIPMENT PER OSHA (OccupationalSafetyandHealthAdministration)
STANDARDS.
IMPORTANT: Dryer must be installedinalocation/environment, which theambient
temperatureremainsbetween40° F (4.44° C)and130°F (54.44° C).

4American Dryer Corp. 113363-6
SECTIONII
SPECIFICATIONS/COMPONENTIDENTIFICATION
A. SPECIFICATIONS
Shaded areas are stated in metric equivalents 9/27/04
*Heat reclaimer available on gas models and steam models. Contact factory for changes to specifications and
drawings.
NOTE: ADCreserves the right to make changes in specifications at any time without notice or
obligation.
MAXIMUM CAPACITY (DRY WEIGHT) 120 lbs 54.43 kg
TUMBLER DIAMETER 44-1/8” 112.08 cm
TUMBLER DEPTH 40-9/16” 103.03 cm
TUMBLER VOLUME 35.90 cu ft 1.017 cu m
TUMBLER/DRIVE MOTOR 1 hp 0.75 kW
BLOWER/FAN MOTOR 3 hp 2.24 kW
DOOR OPENING (DIAMETER) 31-3/8” 79.71 cm
DOOR SILL HEIGHT 26-5/8” 67.63 cm
WATER CONNECTION 3/4”-11.5 NH
DRYERS PER 20’/40’ CONTAINER 3 / 7
DRYERS PER 48’/53’ TRUCK 9 / 10
VOLTAGE AVAILABLE 208-480v 3ø 3,4w 50/60 Hz
APPROX. NET WEIGHT 1,370 lbs 621.42 kg
APPROX. SHIPPING WEIGHT 1,430 lbs 648.64 kg
AIRFLOW 2,800 cfm 79.29 cmm
HEAT INPUT 415,000 Btu/hr 104,578 kcal/hr
EXHAUST CONNECTION (DIAMETER) 16” 40.64 cm
COMPRESSED AIR CONNECTION 1/4” Quick Connection
COMPRESSED AIR VOLUME 2.50 cfh 0.07 cmh
INLET PIPE CONNECTION 1-1/4” F.N.P.T.
VOLTAGE AVAILABLE 208-380v 3ø 3,4w 50/60 Hz
APPROX. NET WEIGHT 1,370 lbs 621.42 kg
APPROX. SHIPPING WEIGHT 1,430 lbs 648.64 kg
AIRFLOW 2,800 cfm 79.29 cmm
EXHAUST CONNECTION (DIAMETER) 16” 40.64 cm
COMPRESSED AIR CONNECTION 1/4” Quick Connection
COMPRESSED AIR VOLUME 2.50 cfh 0.07 cmh
OVEN SIZE
kW Btu/hr kcal/hr
72 245,729 61,923
VOLTAGE AVAILABLE 208-480v 3ø 3,4w 50/60 Hz
APPROX. NET WEIGHT 1,450 lbs 657.71 kg
APPROX. SHIPPING WEIGHT 1,500 lbs 680.39 kg
AIRFLOW 2,800 cfm 79.29 cmm
STEAM CONSUMPTION 450 lbs/hr 204.12 kg/hr
OPERATING STEAM PRESSURE 125 psi max 8.62 bar
EXHAUST CONNECTION (DIAMETER) 16” 40.64 cm
COMPRESSED AIR CONNECTION 1/4” Quick Connection
COMPRESSED AIR VOLUME 3.25 cfh 0.09 cmh
BOILER HP (NORMAL LOAD) 13 Bhp
SUPPLY CONNECTION 1-1/4” M.N.P.T.
RETURN CONNECTION 1-1/4” M.N.P.T.
Steam* Electric Gas*

113363-6 www.amdry.com 5
Specifications
NOTE: ADCreserves the right to make changes in specifications at any time without notice or
obligation.

6American Dryer Corp. 113363-6
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 Panel Assembly
5Lint Door
6Wire Diagram (located behind control door)
7Top Console (module) Assembly

113363-6 www.amdry.com 7
2. Dryer Rear View
Illus. No. Description
1Electrical Service Connections
2Top Console
3Heating Unit
4Relay/Wiring Box
5Data Label and Installation Label
6Air Connection
7Exhaust Transition Piece

8American Dryer Corp. 113363-6
SECTIONIII
INSTALLATIONPROCEDURES
Installation should be performed by competent technicians in accordance with local and state codes. In the
absence of these codes, the installationmust conformto applicable American National Standards: 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
codes or ordinances the location must conform with the National Fuel Gas Code ANSI.Z223.1 LATEST
EDITION, 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 dryermust beinstalled onnoncombustiblefloors only.”
2. The dryer must not be installed or stored in an area where it will be exposed to water and/or weather.
3. The dryer is for use in noncombustible locations.
4. Provisions for adequate air supply must be provided as noted in this manual (refer to Fresh Air Supply
Requirements in Section D).
5. Clearance provisions must be made from combustible construction as noted in this manual (refer to Dryer
Enclosure Requirements in Section C).
6. 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).
7. The dryer must be installed with a proper exhaust duct connection to the outside as noted in this manual
(refer to Exhaust Requirements in Section E).
8. 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 shouldbelocated where a minimum amount of exhaust duct will benecessary.
9. The dryer must be installed with adequate clearance for air openings into the combustion chamber.
CAUTION: This dryer produces combustible lint andmust be exhausted totheoutdoors. Every 6
months,inspect theexhaust ductingand removeanylint buildup.

113363-6 www.amdry.com 9
IMPORTANT: Dryer must be installedinalocation/environment, which theambient
temperatureremainsbetween40° F (4.44° C)and130°F (54.44° C).
B. UNPACKING/SETTING UP
Remove protective shipping material (i.e., plastic wrap and/or optional shipping box) from dryer.
IMPORTANT: Dryermust betransported and handled in an upright position at ALLtimes.
The dryer can be moved to its final location while still attached to the skid or with the skid removed. To unskid
the dryer, locate and remove the four (4) lag bolts securing the base of the dryer to the wooden skid. Two (2) are
at the rear base, and two (2) are located in the bottom of the lint chamber. To remove the two (2) lag bolts
located in the lint chamber area, remove the front panel.
Leveling Dryer
1. To level the dryer, place 4-inch (10.16 cm) square metal shims or other suitable material under the base
pads. It is suggested that the dryer be tilted slightly to the rear (refer to the illustration above).
2. If more headroom is needed when moving the dryer into position, the top console (module) may be removed.

10 American Dryer Corp. 113363-6
To Remove Top Console (module):
a. Disconnect the ground wire (A in the illustration below) located at the rear upper left corner of the
dryer.
b. Remove the six (6) sets of nuts and washers (B in the illustration below) holding the console (module)
to the base.
c. Disconnect the white plug connector (C in the illustration below) located on the top of the rear
electric service/relay box (provides power to the heat circuit).
d. Disconnect air connection from the 3-way micro valve.
e. Lift the console (module) off of the dryer base.
IMPORTANT: The dryermust betransported and handled in an upright position at ALLtimes.

113363-6 www.amdry.com 11
C. DRYER ENCLOSURE REQUIREMENTS
Bulkheads and partitions should be made of noncombustible material.
NOTE: Allowancesmust be made for opening the control door.
A38-inches (76.2 cm) for optimum opening of load door.
BThe maximum thickness of the bulkhead for gas dryers is 4-inches (10.16 cm). For electric and steam dryers
the maximum thickness of the bulkhead is 1-inch (2.54 cm) within 3-inches (7.62 cm) from the top of the
control door.
CFor gas and electric dryers a minimum overhead clearance of 12-inches (30.48 cm) is required, providing no
sprinkler is located above the dryer. For steam dryers or if a sprinkler is located above the dryer, 18-inches
(45.72 cm) is required.
DDryer should be positioned 12-inches (30.48 cm) away from the nearest obstruction and 24-inches (60.96
cm) is recommended for ease of installation, maintenance, and service.
E2-inch (5.08 cm) minimum is required for opening the control door.
FFlooring should be level or below dryer cabinet for ease of removing panels during maintenance.
GDryers may be positioned sidewall to sidewall, however a 1/16” (1.5875 mm) minimum allowance must be
made for the opening and closing of the control door, along with the removal of panels during maintenance.
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. 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. An
unrestricted source of air is necessary for each dryer. An airflow of 2,800 cfm (79.28 cmm) must be supplied
to each dryer. As a general rule, an unrestricted air entrance from the outdoors (atmosphere) of a minimum of
3 square feet (0.279 square meters) is required for each dryer.
To compensate for the use of registers or louvers used over the openings, this make-up air must be increased 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.

12 American Dryer Corp. 113363-6
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 six (6) dryers, two (2) unrestricted openings measuring 3 feet by 3 feet (0.91 meters
by 0.91 meters) are 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 airmust be provided from a source free of dry cleaning solvent fumes.
Make-upair thatis contaminatedby drycleaning solventfumes willresult in
irreparable damage to the motors and other dryer components.
NOTE: Component failure due to dry cleaning solvent fumes willVOIDTHEWARRANTY.
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 andmustbeexhausted totheoutdoors.
CAUTION: IMPROPERLY SIZEDOR INSTALLED EXHAUST DUCTWORK CAN
CREATEAPOTENTIAL FIREHAZARD.
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.

113363-6 www.amdry.com 13
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 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. Excluding 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 in
proportion to the number of elbows used.
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.
NOTE: Whenthe exhaustductwork passesthrough awall, ceiling,or roofmade of combustible
materials, the openingmustbe2-inches (5.08cm) largerthan theduct (allthe wayaround).
Theduct mustbecentered within thisopening.
IMPORTANT:It is recommendedthat 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
constructedof sheetmetal orother noncombustiblematerial. Such ductsshall beequivalentin
strength and corrosion resistance to ducts made of galvanized sheet steel not less than
0.0195-inches (26 gauge [0.5 mm]) thick.”
Outside Ductwork Protection
To protect the outside end of the horizontal ductwork from the weather, a 90° 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 180° turn to point the opening downward. In
either case, allow at least twice the diameter of the duct between the duct opening and the nearest obstruction.

14 American Dryer Corp. 113363-6
IMPORTANT: DO NOT use screens, louvers, or caps on the outside opening of the exhaust
ductwork.
2. Single Dryer Venting
Where possible, it is suggested to provide a separate exhaust duct for each dryer. The exhaust duct 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. 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 as long as the minimum cross section area is
provided.
IMPORTANT: The minimum duct size for a gas unit is 16-inches (40.64 cm) for a round duct and
14-1/4” x 14-1/4” (36.2 cm x 36.2 cm) for a square duct. THE DUCTSIZE
MUST NOT BE REDUCED ANYWHEREDOWNSTREAMOFTHE
DRYER.
IMPORTANT: Exhaust back pressure measured by a manometer at each basket (tumbler) exhaust
duct areamust be no less than 0 andmust not exceed0.3 inches (0.74 mb) of water
column(W.C.).
It is suggested that the ductwork from each dryer not exceed 20 feet (6.09 meters) with no more than two
(2) elbows (excluding dryer connections). If the ductwork exceeds 20 feet (6.09 meters) or has numerous
elbows, the cross-sectional area of the ductwork must be increased in proportion to the length and number
of elbows in it. In calculating duct size, the cross-sectional area of a square or rectangular duct must be
increased twenty percent (20%) for each additional 20 feet (6.09 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 40 feet (12.19 meters), and each 45º elbow is equivalent to an additional
20 feet (6.09 meters).
SingleDryer Venting

113363-6 www.amdry.com 15
IMPORTANT: For extended ductwork runs, the cross section area of the ductwork can only be
increased to an extent. Maximum proportional ductwork runscannotexceed20 feet
(6.09meters) morethan theoriginal limitationsof 20feet (6.09meters)with two(2)
elbows. Whenthe ductwork approachesthe maximumlimits asnoted inthis manual,
aprofessional heating,ventilating, andair-conditioning (HVAC) firm shouldbe
consultedfor properventinginformation.
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.
NOTE: Whenthe exhaustductwork passesthrough awall, ceiling,or roofmade of combustible
materials, the openingmustbe2-inches (5.08cm) largerthan theduct (allthe wayaround).
Theduct must becentered withinthisopening.
3. Multiple Dryer (Common) Venting
If it is not feasible to provide separate exhaust ducts for each dryer, ducts from individual dryers may be
channeled into a “common main duct.” The individual ducts should enter the bottom or side of the main
duct at an angle not more than 45° in the direction of the flow and should be spaced at least
48-3/4” (123.82 cm) apart. The main duct should be tapered, with the diameter increasing before each
individual 16-inch (40.64 cm) duct.
IMPORTANT: When exhausted into a multiple (common) exhaust line, a back draft dampermustbe
installedat eachdryerduct.
IMPORTANT: No more than four (4) dryers should be connected to one (1) main common duct.
The main duct may be any shape or cross-sectional area, as long as the minimum cross section area is
provided. The illustration on the following page shows the minimum cross section area for multiple dryer
round or square venting. These figures must be increased 10 square inches (64.52 square centimeters)
when rectangular main ducting is used, and the ratio of duct width to depth should not be greater than
3-1/2 to 1. These figures must be increased in proportion if the main duct run to the last dryer to where it
exhausts to the outdoors is unusually long (over 20 feet [6.09 meters]) or has numerous elbows (more than
two [2]) in it. In calculating ductwork size, the cross-sectional area of a square or rectangular duct must
be increased twenty percent (20%) for each additional 20 feet (6.09 meters). The diameter of a round
exhaust must be increased ten percent (10%) for each additional 20 feet (6.09 meters). Each 90° elbow
is equivalent to an additional 40 feet (12.19 meters) and each 45° elbow is equivalent to an additional 20
feet (6.09 meters).

16 American Dryer Corp. 113363-6
MultipleDryerVenting
16-Inch(40.64 cm) DiameterMinimum Exhaust Connectionsat CommonDuct
IMPORTANT: For extended ductwork runs, the cross section area of the ductwork can only be
increased to an extent. Maximum proportional ductwork runscannotexceed20 feet
(6.09meters) morethan theoriginal limitationsof 20feet (6.09meters)with two(2)
elbows. Whenthe ductwork approachesthe maximumlimits asnoted inthis manual,
aprofessional heating,ventilating, andair-conditioning (HVAC) firm shouldbe
consultedfor properventinginformation.
IMPORTANT: Exhaust back pressure measured by a manometer in the exhaust ductmust be noless
than 0 andmust not exceed0.3 inches (0.74 mb) of water column (W.C.).
The 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.
NOTE: Whenthe exhaustductwork passesthrough awall, ceiling,or roofmade of combustible
materials, the openingmustbe2-inches (5.08cm) largerthan theduct (allthe wayaround).
The ductmust becenteredwithin thisduct.