American Dryer Corp. Wet Wash ML-79 Administrator Guide

ADC Part No. 113026
ML-79 WET WASH
Installation/Operator's Manual
For replacement parts, contact the distributor 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]
122298GS/mt
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 minimum le risque
d’incendie ou d’explosion ou pour 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 voisinage de 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.
L’installation et l’entretien doivent être assurés
par un installateur ou un service d’entretien
qualifié ou par le fournisseur de gaz.

Retain This Manual In A Safe Place For Future Reference
Replacement parts can be obtained from your distributor or the ADC factory. When ordering replacement parts from the
factory, you can FAX your order toADC at [phone] or telephone your orders directly to the ADCPartsDepartmentat
[phone]. Please specify the dryermodelnumber andserialnumberin addition to thedescription andpartnumber,so
that your order is processed accurately and promptly.
Theillustrationson the following pages may not depict your particular dryer exactly. The illustrations are a composite of the
various dryer models. Be sure to check the descriptions of the parts thoroughly before ordering.
DATE OF PURCHASE MODEL NO.
DISTRIBUTORS NAME
Serial Number(s)
ML-79 WW
“IMPORTANT NOTE TO PURCHASER”
Information must be obtained 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.
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.
OBSERVEALL SAFETY PRECAUTIONS displayed on the equipment or specified in the installation/operator's manual
included with the dryer.
The following “FOR YOUR SAFETY” caution must be posted near the dryer in a prominent location.
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.
Important
For your convenience, log the following information:

IMPORTANT
YOU MUST DISCONNECT and LOCKOUT THE ELECTRIC SUPPLY and THE GAS
SUPPLY BEFORE ANY COVERS or GUARDS ARE REMOVED FROM THE MA-
CHINE TO ALLOW ACCESS FOR CLEANING, ADJUSTING, INSTALLATION, or
TESTING OF ANY EQUIPMENT per OSHA(Occupational Safety and Health Administra-
tion) STANDARDS.
CHILDREN SHOULD NOTBEALLOWED TO PLAY ON OR NEAR THE DRYERS.
WARNING
CHILDREN SHOULD BESUPERVISED IF NEAR DRYERS IN OPERATION.
DRYER(S) SHOULD NEVER BE LEFT UNATTENDED WHILE IN OPERATION.
CAUTION
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 door switch or the heat circuit 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 displayed on the equipment and/or
specified in the installation/operator's manual included with the dryer.
Dryers must not be installed or stored in an area where it will be exposed to water and/or
weather.
The wiring diagram for the dryer is located in the front electrical control box area.
DRYER MUST NEVER BE OPERATED WITHOUT THE LINT FILTER/SCREEN IN
PLACE...EVEN IF AN EXTERNAL LINT COLLECTION SYSTEM IS USED.
WARNING

Table of Contents
SECTION I .........................................................................................................3
IMPORTANT INFORMATION
A. Receiving and Handling ............................................................................................................... 3
B. Safety Precautions ....................................................................................................................... 4
SECTION II ........................................................................................................6
SPECIFICATIONS/COMPONENT IDENTIFICATION
A. Specifications .............................................................................................................................. 7
B. Component Identification............................................................................................................. 8
SECTION III.......................................................................................................9
INSTALLATION PROCEDURES
A. Location Requirements................................................................................................................ 9
B. Unpacking/Setting Up ............................................................................................................... 10
C. Dryer Enclosure Requirements ...................................................................................................11
D. Make Up Air Requirements ...................................................................................................... 12
E. Exhaust Requirements............................................................................................................... 14
F. Electrical Information ................................................................................................................ 18
G. Gas Information ........................................................................................................................ 21
H. Air Information ......................................................................................................................... 25
I. Preparation For Operation/Start-Up .......................................................................................... 26
J. Preoperational Tests .................................................................................................................. 27
K. Preoperational Instructions ......................................................................................................... 28
L. Shut Down Instructions .............................................................................................................. 28
SECTION IV.....................................................................................................29
SERVICE/PARTS INFORMATION
A. Service ..................................................................................................................................... 29
B. Parts ......................................................................................................................................... 29
SECTION V ......................................................................................................30
WARRANTY INFORMATION
A. Returning Warranty Card(s) ...................................................................................................... 30
B. Parts ......................................................................................................................................... 30
C. Returning Warranty Card(s) ...................................................................................................... 30

SECTION VI.....................................................................................................32
ROUTINE MAINTENANCE
A. Cleaning ................................................................................................................................... 32
SECTION VII ...................................................................................................34
TROUBLESHOOTING
SECTION VIII ..................................................................................................41
TECHNICAL INFORMATION
SECTION IX .....................................................................................................42
PROCEDURE FOR FUNCTIONAL CHECK OF
REPLACEMENT COMPONENTS
AQUATEX HUMIDITY SENSOR INSTRUCTIONS ....................................................................44

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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 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. Dryer/
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 theADC Traffic Manager at [phone].
IMPORTANT:The dryer must be transported and handled in an upright position at all times.

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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 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 machine, 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 solvent 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 also may be a fire hazard.

5
7. A program should be established for the inspection and cleaning of lint in the burner area, exhaust duct
work, 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 duct work 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 switches, the lint drawer switch, or the heat
safety circuit ever be disabled.
WARNING: PERSONAL INJURY 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 complete can
create a fire hazard.
12. Replace leaking flexible steam hoses or other fixtures immediately. DO NOT operate the dryer with leaking
flexible hoses. PERSONAL INJURY MAY RESULT.
13. READ and FOLLOW ALL CAUTION and DIRECTION LABELS ATTACHED TO THE DRYER.
WARNING: YOU MUST DISCONNECT and LOCKOUT THE ELECTRIC SUPPLY and
THE GAS SUPPLY BEFORE ANY COVERS orGUARDS ARE REMOVED
FROM THE MACHINE TO ALLOW ACCESSFOR CLEANING, ADJUSTING,
INSTALLATION, or TESTING OF ANYEQUIPMENT per OSHA (Occupational
Safety and Health Administratio) STANDARDS.

6
Basket Diameter 37" 94 cm
Basket Depth 36" 152.4 cm
Basket Motor 1 HP .746 kw
Door Opening (Diameter) 31-3/8" 79.7 cm
Basket Volume 22.4 cu. ft. .634 cu. m.
Dryers per 20'/40' container 10/20
Dryers per 45'/48" Truck 24/24
Voltage Available 120-460v / 10-30 / 50/60 Hz
Approx. Weight (Uncrated) 721 lbs. 327 kg
Approx. Weight (Crated) 771 lbs. 349.7 kg
Heat Input 200,000 btu/hr 50,400 kcal/hr
Airflow 1,200 cfm 33.98 cmm
Inlet Pipe Size 3/4* 1.91 cm
Voltage Available 208-460v / 10-30 / 50/60 Hz
Approx. Weight (Uncrated) 721 lbs. 327 kg
Approx. Weight (Crated) 771 lbs. 349.7 kg
Airflow 1,200 cfm 33.98 cmm
SECTION II
SPECIFICATIONS / COMPONENT IDENTIFICATION
A. SPECIFICATIONS
GasElectric
* Minimum of 3/4” pipe must be supplied to the gas inlet for each dryer
Shaded areas are stated in metric equivalents
IMPORTANT:Dryers must be provided with a clean, dry, regulated 80 PSI
(+/- 10 PSI) air supply.
NOTE:ADCreserves the right to make changes in specifications at any time, without notice or
obligation.

7
Specifications
ML-79 WET WASH

8
Illus. No. Description
1Controls
2Control (top access) Door Assembly
3Main Door Assembly (Left hand shown)
4Lint Compartment Area (lint screen located behind door)
5Data Label and Installation Label (located behind control [service] door)
6Emergency Stop
B. COMPONENT IDENTIFICATION
1. Dryer Front View

9
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 to applicable American national Standards: 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.
A. LOCATION REQUIREMENTS
Before installing the dryer be sure the location controls to local codes and ordinances. In the absence of such
codes or ordinances the location must conform with 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.
1. The dryer must be installed on a sound level floor capable of supporting its weight. It is recommended
that carpeting be removed from the floor area that the dryer is to rest on.
2. The dryer must not be installed or stored in an area where it will be exposed to water 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
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. Dryer must be exhausted to the outdoors. 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 the manual.
Refer to Exhaust Requirements in section E.
IMPORTANT: Dryer should be located where a minimum amount of exhaust duct will be necessary.
9. Provisions must be made for an adequate air supply to be brought to the dryer. Refer to make up air
requirements on page 12.

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B. UNPACKING AND SETTING UP
Remove protective shipping material (i.e., plastic wrap and optional shipping box) from dryer.
IMPORTANT: Dryer must be transported and handled in an upright position at all time.
The dryer can be moved to its final location with or without the skid attached. To un-skid the dryer, locate and
remove the four (4) bolts securing the base of the dryer to the wooden skid. Two (2) are at the rear base (remove
the back panel for access), and two (2) are located in the bottom of the lint chamber. To remove the two (2) bolts
located in the lint chamber area, remove the lint door.
With the skid removed, to make it easier to slide the dryer into its final position, slightly lower ALL four
(4) leveling legs, so the dryer will slide on the legs instead of the base frame.
To increase bearing life and improve efficiency, the dryer should be titled slightly to the rear.
The basket (tumbler) is supported during shipping by a wooded block. REMOVE THIS BLOCK BEFORE
STARTINGTHEDRYER.
IMPORTANT: For microprocessor (computer) models, this wooden block must be removed before
connecting power to the dryer or irreparable damage to the basket (tumbler) will result.
The lint coops of ALL MW-79 dryers are supported during shipping by a bracket. REMOVE THIS BRACKET
BEFORE STARTING THE DRYER.
Before operating machine, the humidity sensor located behind the control door must be placed on the outer top
of the dryer (see page 47 for installation intructions). Check to ensure the relay box cover has been put on and
the air filter assembly connected. Forty (40) p.s.i. is required for the air filter system.
1. LEVELING DRYER
The dryer is equipped with four (4) leveling legs, one at each corner of the base. Two (2) are located at the rear
of the dryer base, and two (2) are located in the lint chamber (coop). To increase bearing life and improve
efficiency, the dryer should be tilted slightly to the rear.

11
C. DRYER ENCLOSURE REQUIREMENTS
Bulkheads and partitions should be made of noncombustible materials and must be located a minimum of
twelve (12) inches (18 inches 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 be a minimum of four (4) inches and must not extent more
than four (4) inches to the rear of the front. The bulkhead facing must not be closed in all the way to the top of
the dryer. A one (1) inch clearance is required.
NOTE: Allowances must be made for opening the control door.
Dryers may be positioned side wall to side wall. However, a 1/16” minimum allowance must be made for
opening and closing of the control door and the lint door. It is suggested that the dryer be positioned about two
(2) feet 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.
NOTE: The top on the dryer extend 6” above the control door. If measuring from the control
door the minimum header clearance.

12
IMPORTANT: Even though a minimum of only 12 inches is required, 18 inches or more is
suggested, especially in cases where sprinkler heads are over the installation and
service.
IMPORTANT: When fire sprinkler systems are located above the dryers, a minium of 18 inches
above the dryer console (module) is required. Dryers may be positioned side
wall to side wall however, a 1/16” minimum allowance is required between
dryers (or wall) for base of installation and maintenance. Allowances mustbe
made for the opening and closings of the control door and the lint door.
D. MAKE UP AIR REQUIREMENTS
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 air must be continually replenished from the outdoors. If
the make-up air is inadequate, drying time and 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 air flow of 1,200 cfm (cubic feet per minute)must be
supplied to each gas and electric dryer. As a general rule, an unrestricted air entrance from the outdoors
(atmosphere) of a minimum of 1-1/2 square feet is required for each dryer.

13
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 openingsshould not be located in an
area directly near where exhaust vents exit the building.
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 ALLof the dryers.
EXAMPLE: For a bank of four (4) dryers, two (2) unrestricted openings measuring 2 feet by
1-1/2 feet (6 square feet) 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 airmust beprovided from a source free of dry cleaning solvents 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.

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E. EXHAUST REQUIREMENTS
1. General Exhaust Duct Work Information
Exhaust duct work should be designed and installed by a qualified professional. Improperly sized duct work
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.
CAUTION: Dryer must be exhausted to the outdoors.
CAUTION: Improperly sized or installed exhaust dust work can create a potential fire hazard.
The duct work should be laid out in such a way that the duct work travels as directly as possible to the outdoors
with as few turns as possible. Single or independent dryer venting is recommended.
When single drying venting is used the length of ductwork from the dryer to the outside exhaust outlet should not
exceed fifteen (15) feet. The minimum diameter of the duct work must be at least 10 inches. Even though the
dryer exhaust duct for gas and electric units is only 8”. The shape of the duct work 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 or 45º
angles instead. The radius of the elbows should preferably be 1-1/2 times the diameter of the duct. Including
basket (tumbler) and 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 duct work must beincreased.
ALL duct work 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 will
connected. ALL duct work joints must be taped to prevent moisture and lint from escaping into the building.
The inspection door should be installed at strategic points in the exhaust duct work for periodic inspection and
clean-out of lint from the duct work.
IMPORTANT: Exhaust back pressure measured by a manometer in the exhaust duct should not
exceed .3 inches of the water column.
IMPORTANT: Minimum duct work diameter is 10 inches.
IMPORTANT: Where the exhaust duct work passes through a wall, ceiling, or roof made of
combustible materials, the opening must be 2 inches larger, all the way around, the duct.
The duct must be centered within this opening.
a. Outside Duct Work Protection
1. To protect the outside end of horizontal duct work from the weather, a 90º elbow bent downward should be
installed where the exhaust exits the building. If the duct work 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 between the duct opening and the nearest obstruction.
IMPORTANT: DO NOT use screens or caps on the outside of opening of exhaust duct work.

15
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 duct work travels as directly as possible to the outdoors with as few turns as
possible. It is suggested that the use of 90º turns in the ducting be avoided; use 30º or 45º angles instead. The
shape of the exhaust duct work is not critical so long as the minimum cross section area is provided.
IMPORTANT: Minimum duct size for dryer is 10 inches for a round duct or 9” x 9” for a square duct.
The duct size must not be reduced anywhere down stream of the dryer.
IMPORTANT: Exhaust back pressure measured by a manometer at each basket (tumbler) exhaust
duct area should not exceed .3 inches of water column.

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It is important that the duct work from each dryer not exceed fifteen (15) feet with no more than (2) elbows
(excluding dryer connections and outside exhaust outlets). If the duct work exceeds fifteen (15) feet or has
numerous elbows, the cross section area of the duct work 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 (20) percent for each additional fifteen (15) feet. The diameter of a round exhaust duct
should be increased ten (10) percent for each additional fifteen (15) feet. Each 90º elbow is equivalent to an
additional thirty (30) feet, and each 45º elbow is equivalent to an additional fifteen (15) feet.
IMPORTANT: For extended duct work runs, the cross section area of the duct work can only be
increased to an extent. Maximum proportional duct work runs cannot exceed fifteen
(15) feet more than the original limitations of the maximum limit noted in this manual,
a professional heating venting air conditioning (HVAC) firm should be consulted for
proper venting information.
ALL duct work 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 duct work 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 duct work for periodic inspection and
clean-out of lint from the duct work.