Maytag MD-170 Administrator Guide

020800JEV/abe ADC Part No. 113024
MD-170
Installation/Operator's Manual
For replacement parts, contact the distributor from which the dryer
was purchased or contact:
Maytag Co.
403 West Fourth St North
Newton, Iowa 50208
[phone]
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 DOYOU 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
DATE OF PURCHASE MODEL NO.
DISTRIBUTORS NAME
Serial Number(s)
MD-170
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.
Our 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 and 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. Manufacturer 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:
For replacement parts, contact the distributor from which the dryer was purchased or contact:
Maytag Co.
403 West Fourth St North
Newton, Iowa 50208
[phone]

IMPORTANT
YOU MUST DISCONNECT and LOCKOUT THE ELECTRIC SUPPLY and THE GAS
SUPPLY BEFOREANY COVERS or GUARDSARE REMOVED FROM THE MACHINE
TOALLOW ACCESS FOR CLEANING, ADJUSTING, INSTALLATION, or TESTING
OFANY EQUIPMENT per OSHA (Occupational Safety and HealthAdministration) STAN-
DARDS.
CHILDREN SHOULD NOT BE ALLOWED TO PLAY ON OR NEAR THE DRYERS.
WARNING
CHILDREN SHOULD BE SUPERVISED IF NEAR DRYERS IN OPERATION.
DRYERS SHOULD NEVER BE LEFT UNATTENDEDWHILE IN OPERATION.
CAUTION
FOR YOUR SAFETY
DO NOT DRYMOP HEADS INTHE 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: Lor des opérations d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 OBSERVE ALL SAFETY PRECAUTIONS displayed on the equipment and
specified in the installation and operator's manual included with the dryer.
Dryers must not be installed or stored in an area where it will be exposed to water 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 and SCREEN
IN PLACE, EVEN IFAN EXTERNALLINT COLLECTION SYSTEM IS USED.
WARNING

Table of Contents
SECTION I
IMPORTANT INFORMATION ............................................................................... 3
A. RECEIVING and HANDLING................................................................................................... 3
B. SAFETY PRECAUTIONS ........................................................................................................ 4
SECTION II
SUPER AD-30 SPECIFICATIONS.......................................................................... 6
A. SPECIFICATIONS (Gas and Steam Models) ............................................................................. 6
B COMPONENT IDENTIFICATION ........................................................................................... 8
SECTION III
INSTALLATION PROCEDURES ......................................................................... 10
A. LOCATION REQUIREMENTS .............................................................................................. 10
B. UNPACKING/SETTING UP .................................................................................................. 11
C. DRYER ENCLOSURE REQUIREMENTS ............................................................................. 13
D. FRESHAIR SUPPLY .............................................................................................................. 14
E. EXHAUST REQUIREMENTS ................................................................................................ 15
F. ELECTRICALINFORMATION .............................................................................................. 21
G. GAS INFORMATION .............................................................................................................25
H. STEAM INFORMATION ....................................................................................................... 29
I. PREPARATION FOR OPERATION / START-UP................................................................... 33
J. PREOPERATIONALTESTS ................................................................................................... 34
K. SHUT DOWN INSTRUCTIONS ........................................................................................... 36
L. COMPRESSEDAIR REQUIREMENTS ................................................................................. 37
SECTION IV
SERVICE / PARTS INFORMATION.................................................................... 38
A. SERVICE................................................................................................................................. 38
B. PARTS ..................................................................................................................................... 38
SECTION V
WARRANTY INFORMATION .............................................................................. 39
A. RETURNING WARRANTY CARD(S) ................................................................................... 39
SECTION VI
ROUTINE MAINTENANCE .................................................................................. 40
A. CLEANING ............................................................................................................................ 40
B. ADJUSTMENTS ..................................................................................................................... 42
C. LUBRICATION ....................................................................................................................... 42

SECTION VII
TROUBLESHOOTING ........................................................................................... 43
SECTION VIII
REVERSING TIMER SPIN / DWELL ADJUSTMENTS .................................. 60
SECTION IX
DATA LABEL LOCATION/INFORMATION ...................................................... 61
SECTION X
PROCEDURE FOR FUNCTIONAL CHECK OF REPLACEMENT
COMONENTS ..........................................................................................................63
SECTION XI
BURNER AND LINT (TUMBLER) CHAMBER MANUAL RESET
HI-LIMIT INSTRUCTIONS .............................................................................. 66

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 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.
The manufacturer assumes no responsibility for freight claims or damages.
6. If you need assistance in handling the situation, please contact the manufacturer's Traffic Manager at (508)
678-9000.
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 manualmust 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. PERSONALINJURY 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 the manufacturer 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 solvents will create a fire
hazard.
WARNING:DO NOT use heat for drying articles that contain plastic, foam, sponge rubber, or
similarly textured rubber materials. Drying in a heated tumbler (basket) 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 heating unit area, exhaust duct
work, and inside 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.
NOTE: Failure to do so will VOID THE WARRANTY.
9. UNDER NO CIRCUMSTANCES should the dryer door switches, lint door switch, heat safety circuit ever
be disabled.
WARNING: PERSONAL INJURYor 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 steam pressure. Excessive steam pressure can
damage steam coil and/or harm personnel.
13. Replace leaking flexible hoses or other steam fixtures immediately. DO NOT operate the dryer with leaking
flexible hoses. PERSONAL INJURY MAY RESULT.
14. 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 orTHE STEAM SUPPLY BEFOREANY COVERS or
GUARDSARE REMOVED FROM THE MACHINE TOALLOWACCESS
FOR CLEANING,ADJUSTING, INSTALLATION, or TESTING OFANY
EQUIPMENT per OSHA (Occupational Safety and HealthAdministration)
STANDARDS.

6
SECTION II
SPECIFICATIONS / COMPONENT IDENTIFICATION
A. SPECIFICATIONS (GAS and STEAM)
Gas
Steam
IMPORTANT: Gas dryers and steam dryers must be provided with a clean, dry, regulated 80 PSI
±10 PSI (552 kPa ± 0.69 kPa) air supply.
NOTE: The manufacturer reserves the right to make changes in specifications at any time, without
notice or obligation.
Maximum Capacity (Dry Weight) 170 lbs. 77.1 kg
Basket Diameter 51-1/2" 130.8 cm
Basket Depth 42-1/2" 107.9 cm
Basket Motor 1 HP .746 kw
Blower Motor 7-1/2 HP 5.6 kw
Door Opening (Diameter) 31-3/8" 79.7 cm
Basket Volume 51.2 cu. ft. 1.45 cu. m.
Dryers Per 20’/40’Container 3/7
Dryers Per 45’/48’Truck 8/8
Voltage Available 208-600v / 3ø / 3, 4w 50/60 Hz
Heat Input 550,000 btu/hr 138,600 kcal/hr
Approx. Weight (Uncrated) 1,900 lbs. 861.3 kg
Approx. Weight (Crated) 2,065 lbs. 936.1 kg
Airflow 3,700 cfm 104.75 cmm
Inlet Size 1-1/2" 3.81 cm
Compressed Air Connection 1/8" F.P.T. ---
Compressed Air Requirement 2.5 cfm @ 80 PSI .007 cmm @ 552 kPa
Voltage Available 208-600v / 3ø / 3, 4w 50/60 Hz
Approx. Weight (Uncrated) 2,050 lbs. 929.3 kg
Approx. Weight (Crated) 2,220 lbs. 1,006.3 kg
Heat Input 19 Bhp
Steam Consumption 725 lbs/hr 329.1 kg/hr
Airflow 4,400 cfm 124.56 cmm
Inlet Size 1-1/2" 3.81 cm
Return Size 1-1/2" 3.81 cm
Compressed Air Connection 1/8" F.P.T ---
Compressed Air Requirement 6 cfh @ 80 PSI .017 cmm @ 552 kPa
Shaded areas are stated in metric equivalents

7
NOTE: Operating height of steam dryer is 101-inches (256.54 centimeters).
NOTE: The manufacturer reserves the right to make changes in specifications at any time, without
notice or obligation.
Specifications
MDG-170 (Gas)
MDS-170 (Steam)

8
B. COMPONENT IDENTIFICATION
1. Dryer Front View
Illus. No. Description
1 Microprocessor Control/Keyboard (Touchpad) Panel Assembly (Controls)
2 Control (top access) Door Assembly
3 Main Door Assembly
4 Lint Door Assembly
5 Lint Drawer
6 Wire Diagram (located Behind Control Door)
7 Top Console (Module)Assembly
8 Data Label and Installation Label

9
2. Dryer Rear View
Illus. No. Description
1 Basket (Drive) Motor Assembly
2 Blower Motor Mount Assembly
3 Idler Bearing Mount Assembly
4 Tumbler Bearing Mount Assembly
5* Electric Service Relay Box
6 Heating Unit
7 Data Label and Installation Label
8 1/8" Compressed Air Supply Inlet (Behind Gusset)
9 Side Access Opening
10 Front Access Opening
11 Impellor (fan/blower)Assembly
* Electric service connections 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 to applicable AMERICAN NATIONAL STANDARDS:
ANSI.Z223.1-LATEST EDITION (National Fuel Gas Code)
and/or
ANSI/NFPA NO. 70-LATEST EDITION (National Electric Code)
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.
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 and/or weather.
3. Provisions for adequate air supply must be provided as noted in this manual (refer to Fresh Air Supply 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 (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 the 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 should be located where a minimum amount of exhaust duct will be necessary.

11
B. UNPACKING/SETTING UP
Remove protective shipping material (i.e., plastic wrap, and/or optional shipping box) from dryer.
IMPORTANT: Dryer must be transported and handled in an upright position at all times.
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
located 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) lag bolts located in the lint chamber area, remove the lint drawer and the four
(4) Phillips head screws securing lint door in place.
1. Leveling Dryer
a. To level 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 illustration above).
2. The V-belts are disconnected from the basket drive motor for shipping. Reconnect V-belts before starting
the dryer.
a. To Reconnect V-belts ...
1) Remove hardware holding the back (belt) guard and remove guard from the dryer.
2) Lay one (1) belt into motor sheave (pulley) groove and wind belt into corresponding groove of idler
pulley by rotating the idler pulley by hand. Rotate the idler pulley an extra turn or two to insure that the
belt is tracking properly in the motor sheave (pulley) and idler pulley grooves without twisting.

12
5) Lift the console (module) off of the dryer base.
IMPORTANT: The dryer must be transported and handled in an upright position at all times.
2) Remove the eight (8) set of
nuts and washers (B) holding
the console (module) to base.
3) Disconnect the white plug
connector (C) located on the top
of the rear electric service/
relay box (provides power to
the heat circuit).
4) Disconnect air connection from
the 3-way micro valve.
1) Disconnect the ground wire (A) at the Rear Upper Left Hand
Corner of Dryer.
4. Exhaust Duct Work
NOTE: ATransition Piece for the exhaust is shipped
inside the tumbler (basket). This Transition Piece
is for locations with round exhaust duct work.
a. To install the Transition Piece, align the four (4) clinch studs
into the four (4) clearance holes on the dryer.
b. Using the four (4) free spin wash nuts (included with the
Transition Piece), tighten the wash nuts on to the clinch
studs which will secure the Transition Piece to the dryer.
c. The round duct can now be connected to the dryer.
3. If more headroom is needed when moving dryer into position, the top console (module) may be removed.
a. To Remove Top Console (Module)

13
NOTE: When fire sprinkler systems are located above the dryers, a minimum of 18-inches above the
dryer console (module) is required. Dryers may be positioned side wall to side wall; however,
1 or 2-inches is suggested between dryers (or wall) for ease of installation and maintenance.
Allowances must be made for the opening and closing of the control and lint door.
C. DRYER ENCLOSURE REQUIREMENTS
Even though a 12-inch clearance is acceptable, it is recommended that the rear of the dryer be positioned
approximately two (2) feet from the nearest obstruction (i.e., wall) for ease of installation, maintenance, and
service. Bulkheads and partitions should be made from noncombustible materials. The clearance between the
bulkhead header and the dryer must be a minimum of 4-inches and must not extend more than 4-inches to the
rear of the dryer front. A 2-inch clearance is required between the bulkhead facing and the top of the dryer.
NOTE: Bulkhead facing should not be installed until after dryer is in place. Ceiling area must be
located a minimum of 6-inches above the dryer top console (module) for gas models and
8-inches for steam models.
Even though a minimum of 6-inches above the dryer console (module) is acceptable for gas
models and 12-inches above the dryer console (module) is acceptable for steam models, a
clearance of 12- inches or more (for gas models) and 18-inches or more (for steam models) is
suggested for ease of installation and service.

14
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 motors and other dryer components.
NOTE: Component failure due to dry cleaning solvent fumes willVOIDTHE WARRANTY.
D. FRESH AIR SUPPLY
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 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 3,700 cfm (cubic feet per minute) must be
supplied to each gas dryer and 4,400 cfm for each steam dryer. As a general rule, an unrestricted air entrance
from the outdoors (atmosphere) of a minimum of four (4) square feet is required for each gas dryer and a
minimum of 4.75 square feet for each gas dryer and a minimum of 4.75 square feet for each steam dryer or
126 Kw electrically heated dryer.
To compensate for the use of registers or louvers used over the openings, this make-up air area 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.
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) gas dryers, two (2) openings measuring 3 feet by 4 feet - 0.92 m
by 1.2 m - (24 square feet [2.23 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.

15
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 tumbler (basket) hi-heat
thermostats.
CAUTION: DRYER MUST BE EXHAUSTED TO THE OUTDOORS.
CAUTION:IMPROPERLY SIZED OR INSTALLED EXHAUST DUCT WORK CAN
CREATE APOTENTIAL FIRE HAZARD.
NOTE: When a dryer is exhausted separately, it is recommended that a back draft damper be installed.
NOTE: When dryers are exhausted into a multiple (common) exhaust line, each dryer must be supplied
with a back draft damper.
The exhaust 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 dryer venting is used, the duct work from the dryer to the outside exhaust outlet should not
exceed twenty (20) feet. In the case of multiple (common) dryer venting, the distance from the last dryer to
the outside exhaust outlet should not exceed twenty (20) feet. The shape of the duct work is not critical so
long as the minimum cross section area is provided. It is suggested that the use of 90º turns in ducting be
avoided; use 30º and/or 45º angles instead. The radius of the elbows should preferably be 1-1/2 times the
diameter of the duct. Excluding basket/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 duct work must be increased in proportion to number of
elbows added.
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 ducts to be added should overlap the duct to which it is
connected. ALL duct work joints must be taped to prevent moisture and lint from escaping into the building.
Additionally, 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.
IMPORTANT: Exhaust back pressure measured by a manometer at the dryer exhaust duct area must
not exceed 0.3 inches of water column.
NOTE: 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) than the duct. The duct
must be centered within this opening.

16
a. Outside Duct Work Protection
1) To protect the outside end of horizontal duct work from the weather, a 90° elbow bent downward
should be installed where the exhaust exits the building. If the exhaust duct work 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.
IMPORTANT:DO NOT use screens or caps on the outside of opening of exhaust duct work.