American Dryer Corp. ML-145 User manual

122999SL/tcosta ADC Part No. 450429
ML-145 / ML-170
Service Manual
Phase 6 Microprocessor Controls
and
Timer Controls
American Dryer Corporation
88 Currant Road
Fall River, MA 02720-4781
Telephone: [phone] / Fax: [phone]
e-mail: [email protected]

Retain This Manual In A Safe Place For Future Reference
American Dryer Corporation products embody advanced concepts in engineering, design, and safety. If this product is
properly maintained, it will provide many years of safe, efficient, and trouble-free operation.
ONLY qualified technicians should service this equipment.
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.
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:
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 ADCParts Departmentat
[phone]. Please specify the dryermodelnumber andserialnumberin addition to thedescription andpartnumber,so
that your order is processed accurately and promptly.
The illustrations on the following pages may not depict your particular dryer exactly. The illustrations are a composite from
the various dryer models. Be sure to check descriptions of the parts thoroughly before ordering.
DATE OF PURCHASE MODEL NO.
DISTRIBUTORS NAME
Serial Number(s)
ML-145 / ML-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.
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.

IMPORTANT
YOU MUST DISCONNECT and LOCKOUT THE ELECTRIC SUPPLY and THE GAS
SUPPLY or THE STEAM SUPPLY BEFORE ANY COVERS or GUARDS ARE
REMOVEDFROMTHEMACHINETOALLOWACCESS FORCLEANING,ADJUST-
ING, INSTALLATION, or TESTING OF ANY EQUIPMENT per OSHA (Occupational
Safety and Health Administration)STANDARDS.
CHILDREN SHOULD NOT BE ALLOWED TO PLAY ON OR NEAR THE DRYER(S).
WARNING
CHILDREN SHOULD BE SUPERVISED IF NEAR DRYERS IN OPERATION.
DRYERS SHOULD NEVER BE LEFT UNATTENDED WHILE IN OPERATION.
CAUTION
FOR YOUR SAFETY
DO NOT DRY MOP HEADS IN THE DRYER.
DO NOT USE DRYER IN THE PRESENCE OF DRY CLEANING FUMES.
WARNING
UNDERNOCIRCUMSTANCESshouldthedoorswitchortheheatcircuitdevicesever
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 OBSERVEALLSAFETYPRECAUTIONSdisplayedon theequipmentand/or
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/SCREEN IN
PLACE, EVEN IF AN EXTERNAL LINT COLLECTION SYSTEM IS USED.
WARNING

Table of Content
SECTION I
IMPORTANT INFORMATION.......................................................................... 3
A. Safety Precautions ...................................................................................................................... 3
SECTION II
ROUTINE MAINTENANCE .............................................................................. 5
A. Cleaning ..................................................................................................................................... 5
B. Adjustments ............................................................................................................................... 6
C. Lubrication ................................................................................................................................. 6
SECTION III
INSTALLATION REQUIREMENTS ................................................................. 7
A. Enclosure, Air Supply, and Exhaust Requirements ........................................................................ 7
B. Electrical and Gas Requirements ................................................................................................. 7
C. Operational Service Check Procedure ........................................................................................ 8
SECTION IV
DESCRIPTION OF PARTS.............................................................................. 10
A. Control Panel (Microprocessor)................................................................................................ 10
B. Control Panel (Non-Microprocessor) ....................................................................................... 10
C. Control Box ............................................................................................................................. 10
D. HSI (Hot Surface Ignition) Module (Gas Models Only) ..............................................................11
E. Gas Burner Assembly ................................................................................................................11
F. Drive Motor ..............................................................................................................................11
G. Blower Motor and Impellor (Gas and Steam) ............................................................................ 12
H. Idler Assembly.......................................................................................................................... 12
I. Tumbler (Basket) Bearing and Pulley Arrangement ..................................................................... 12
J. Tumbler (Basket) ...................................................................................................................... 13
K. Main Door Switch .................................................................................................................... 13
L. Sail Switch (Gas Models Only) ................................................................................................. 13
M. Hi-Limit (Gas Models Only) ..................................................................................................... 14
N. Automatic Reset Thermostat ..................................................................................................... 14
O. Lint Drawer .............................................................................................................................. 14
P. Lint Drawer Switch................................................................................................................... 15
Q. Steam Damper System ............................................................................................................. 15
R. Compressed Air Requirements .................................................................................................. 15
S. Temperature Sensor Bracket (Non-Computer).......................................................................... 15

SECTION V
SERVICING....................................................................................................... 16
Introduction.................................................................................................................................... 16
A. Computer Controls ................................................................................................................... 16
B. Ignition Controls ....................................................................................................................... 18
C. Thermostats.............................................................................................................................. 21
D. Sail Switch Assembly (Gas Models Only) .................................................................................. 22
E. Front Panel and Main Door Assemblies..................................................................................... 23
F. Pulleys ...................................................................................................................................... 25
G. Tumbler (Basket) Assembly ...................................................................................................... 27
H. Bearings ................................................................................................................................... 29
I. V-Belts..................................................................................................................................... 31
J. Motors ..................................................................................................................................... 32
K. Impellor.................................................................................................................................... 33
L. Lint Drawer Assembly .............................................................................................................. 33
SECTION VI
TROUBLESHOOTING..................................................................................... 35
SECTION VII
ELECTRICAL TROUBLESHOOTING ...........................................................41
SECTION VIII
PHASE 6 OPL SYSTEM DIAGNOSTICS ....................................................... 42
A. Diagnostic (L.E.D. [light emitting diode] Display) Failure Codes................................................. 42
B. L.E.D. (light emitting diode) Display Indicators .......................................................................... 44
C. Phase 6 OPL Microprocessor Controller (Computer) Relay Output L.E.D. (light emitting diode)
Indicators ................................................................................................................................. 45
SECTION IX
L.E.D. DISPLAY/CODES ..................................................................................49
A. L.E.D. Display Operating Status ............................................................................................... 49
B. Phase 6 OPL Microprocessor L.E.D. Displays .......................................................................... 50
C. L.E.D. Codes ........................................................................................................................... 51
D. Computer Logic and Wiring Diagram ........................................................................................ 53
SECTION X
TECHNICAL INFORMATION ........................................................................ 58
A. Motor Plate (High and Low Voltage)......................................................................................... 58
B. Data Label ............................................................................................................................... 59
C. Use a Manometer ..................................................................................................................... 60
D. ML-170 Tool List..................................................................................................................... 61

3
SECTION I
IMPORTANT INFORMATION
A. 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,
wax.
EXPLOSION COULD RESULT.

4
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.
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 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, lint door switch, 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 completed can
create a fire hazard.
12. DO NOT operate steam dryers with more than 125 PSI (8.61 bars) 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 FOLLOWALLCAUTION andDIRECTION LABELSATTACHED TO THEDRYER.
WARNING: YOU MUST DISCONNECT and LOCKOUT THE ELECTRIC SUPPLY and
THE GAS SUPPLY or THE STEAM SUPPLY BEFORE ANY COVERS or
GUARDS ARE REMOVED FROM THE MACHINE TO ALLOW ACCESS
FOR CLEANING,ADJUSTING, INSTALLATION, or TESTING OF ANY
EQUIPMENT per OSHA (Occupational Safety and Health Administration)
STANDARDS.

5
SECTION II
ROUTINE MAINTENANCE
A. CLEANING
A program and/or schedule should be established for periodic inspection, cleaning, and removal of lint from
various areas of the dryer, as well as throughout the duct work system. The frequency of cleaning can best be
determined from experience at each location. Maximum operating efficiency is dependent upon proper air
circulation. The accumulation of lint can restrict this airflow. If the guidelines in this section are met, an ADC
dryer will provide many years of efficient, trouble free, and – most importantly – safe operation.
WARNING: LINT FROM MOST FABRICS IS HIGHLY COMBUSTIBLE. THE
ACCUMULATION OF LINT CAN CREATE A POTENTIAL FIRE HAZARD.
WARNING: KEEP DRYER AREA CLEAR and FREE FROM COMBUSTIBLE
MATERIALS, GASOLINE and OTHER FLAMMABLE VAPORS and
LIQUIDS.
NOTE: Suggested time intervals shown for average usage which is considered six (6) to eight (8)
operational (running) hours per day.
Clean lint drawer and screen every third or fourth load.
NOTE: Frequency can best be determined at each location.
DAILY
(beginning) of each work shift.
Clean lint from the drawer and screen. Inspect lint screen and replace if torn.
WEEKLY
Clean lint accumulation from lint chamber, thermostat, and microprocessor temperature sensor (sensor bracket)
area.
WARNING: To avoid the hazard of electrical shock, discontinue electrical supply to dryer.
STEAM DRYERS
Clean steam coil fins using compressed air and a vacuum cleaner with brush attachment.
NOTE: When cleaning steam coil fins, be careful not to bend the fins. If fins are bent, straighten by
using a fin comb which is available from local air conditioning supply houses.
90 DAYS
Remove lint from tumbler (basket), drive motors, and surrounding areas. Remove lint from gas valve burner area
with a dusting brush or vacuum cleaner attachment.

6
NOTE: To prevent damage, avoid cleaning and/or touching ignitor/flame-probe assembly.
Remove lint accumulation from inside control box and at rear area behind control box.
6 MONTHS
Inspect and remove lint accumulation in customer furnished exhaust duct work system and from dryer’s internal
exhaust ducting.
WARNING: THEACCUMULATION OF LINTIN THE EXHAUST DUCT WORK CAN
CREATEAPOTENTIAL FIRE HAZARD.
WARNING: DO NOT OBSTRUCT THE FLOW OF COMBUSTION and VENTILATION AIR.
CHECK CUSTOMER FURNISHED BACK DRAFT DAMPER IN EXHAUST
DUCT WORK. INSPECT and REMOVE ANYLINTACCUMULATION WHICH
CAN CAUSE DAMPER TO BIND or STICK.
NOTE: A back draft damper that is sticking partially closed can result in slow drying and shut down of
the heat circuit safety switches or thermostats.
NOTE: When cleaning dryer cabinet(s), avoid using harsh abrasives. A product intended for the
cleaning of appliances is recommended.
B. ADJUSTMENTS
7 DAYS AFTER INSTALLATION and EVERY6 MONTHS THEREAFTER
Inspect bolts, nuts, screws, (bearing set screws), nonpermanent gas connections (unions, shut-off valves, orifices,
and ground connections). Motor and drive beltsshould beexamined. Cracked or seriously frayed beltsshould
be replaced. Tighten loose V-belts when necessary. Complete operational check of controls and valves. Complete
operational check of ALL safety devices (door switch, lint drawer switch, sail switch, burner, and hi-limit
thermostats).
C. LUBRICATION
The motor bearings, idler bearings...and under normal/most conditions the tumbler bearings are permanently
lubricated. It is physically possible to re-lubricate the tumbler bearings if you choose to do so even though this
practice is not necessary. Use ShellAlvania#3 or its equivalent. The tumbler bearings used in the dryerdo not
have a great fitting. Provisions are made in the bearing housing for the addition of a grease fitting which can be
obtained elsewhere.
The impellor (fan) shaft bearings should be lubricated every three (3) months.

7
SECTION III
INSTALLATION REQUIREMENTS
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 Fuel
GasCodeANSI.Z223.1-LATEST EDITIONor NationalElectrical CodeANSI/NFPA No.70-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)
or Canadian Electrical Codes Parts 1 & 2 CSA C22.1-1990 or LATEST EDITION (for Electrical Connections).
A. ENCLOSURE, AIR SUPPLY, and EXHAUST REQUIREMENTS
NOTE: The following information is very brief and general. For detailed description, refer to the
“ML-170 Installation Manual” (ADC Part No. 112141).
Bulkheads and partitions around the dryershould be made of noncombustible materials. Allowancesshould be
made for the opening and closing of the control door and lint drawer. Also, allowances should be made in the
rear for ease of maintenance. (Refer to appropriate installation manual for recommended distances and minimum
allowances required.)
When the dryer is operating, it draws in room air, heats it, passes this air through the tumbler (basket), 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 on gas dryers may result, and you also could have premature motor failure from
overheating. The air supply must be given careful consideration to insure proper performance of each dryer.
IMPORTANT: Make-up air must be provided from a source free of dry cleaning fumes. Make-up
air that is contaminated by dry cleaning fumes will result in irreparable damage to
motors and other dryer components.
Exhaust duct work should be designed and installed by a competent technician. Improperly sized duct work will
create excessive back pressure which will result in slow drying, increased use of energy, and shut down of the
burner by the airflow (sail) switch, burner hi-limit or lint chamber hi-heat protector thermostat. (Refer to appropriate
installation manual for more details.)
CAUTION: IMPROPERLY SIZED or INSTALLED EXHAUST DUCT WORK CAN
CREATE A POTENTIAL FIRE HAZARD.
B. ELECTRICAL and GAS REQUIREMENTS
It is your responsibility to haveALL electrical connections made by a properly licensed and competent electrician
to assure that the electrical installation is adequate and conforms with local and state regulations or codes. In the
absence of such codes, ALL electrical connections, material, and workmanship must conform to the applicable
requirements of 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 (for Electrical Connections).

8
IMPORTANT: Failure to comply with these codes or ordinances and/or the requirements stipulated
in this manual can result in personal injury or component failure.
The gas dryer installation must meet the American National Standard, National Fuel Gas Code ANSI Z223.1-
LATEST EDITION, or in Canada, the Canadian Electrical Codes Parts 1 & 2 CSA C22.1-1990 or LATEST
EDITION (for Electrical Connections) as well as, local codes and ordinances, and must be done by a qualified
technician.
NOTE: Undersized gas piping will result in ignition problems and slow drying and can create a safety
hazard.
The dryer must be connected to the type of gas (natural or L.P. [liquid propane]) indicated on the dryer data
label. If this information DOES NOT agree with the type of gas available, contact the distributor who sold
the dryer or contact the factory.
The gas input ratings shown on the dryer data label are for elevations up to 2,000 feet (610 meters), unless
elevation requirements of over 2,000 feet (610 meters) were specified at the time the dryer order was placed with
the factory. The adjustment for dryers in the field for elevations over 2,000 feet (610 meters) are made by
changing the burner orifices. If this adjustment is necessary, contact the distributor who sold the dryer or contact
the factory.
NOTE: Any burner changes must be made by a qualified technician.
C. OPERATIONAL SERVICE CHECK PROCEDURE
1. Turn on electric power to the dryer.
2. To start dryer:
a. Display will read “READY.”
b. Press “D” on the keyboard (touchpad) of microprocessor controller (computer).
c. The dryer will start and the display will show “MANUAL DRYING CYCLE, 00:00 MIN REMAIN.”
NOTE: Pressing keyboard (touchpad) selections “A,” “B,” “C,” “D,” and “F” will also start the dryer.
Six (6) preprogrammed drying cycles (“A” through “F”) have been stored in the computer’s
memory. (Refer to the Computer Operator’s Manual for details.)
3. Make a complete operational check of ALL the operating controls to assure that the timing is correct,
temperature selection switches are functioning, etc.
4. Make a complete operational check of ALL safety-related circuits: door switch(es), hi-limit thermostat, sail
switch, cycling thermostats, etc.
5. For gas dryers a gas pressure test should be taken at the gas valve pressure tap of each dryer to assurethat
the water column pressure is correct and consistent.

9
NOTE: Water column pressure requirements (measured at the pressure tap on the gas valve body):
Natural Gas - 3.5 inches water column (8.7 mb).
L.P. Gas - 10.5 inches water column (26.1 mb).
6. If computer program changes are required, refer to the Phase 6 OPL Operator’s Manual (ADC Part
No. 112147) for details.
7. The dryer should be operated through one complete cycle to assure that no further adjustments are necessary
and that ALL components are functioning properly.
8. Check the electric service phase sequence. While the dryer is operating, check to see if the blower wheel is
rotating in the proper direction. Looking from the front, the blower wheel should spin in the clockwise (CW)
direction. If so, the phasing is correct. If the phasing is incorrect, reverse two (2) leads at connections L1, L2,
or L3 of power supply to the dryer.

10
SECTION IV
DESCRIPTION OF PARTS
A. CONTROL PANEL (MICROPROCESSOR)
Opening the control panel will allow
access to the major components which
include the microprocessor computer
board and the keyboard (touchpad). The
keyboard (touchpad) inputs to the
computer what temperature and program
hasbeen selected. The computer controls
the entire operation of the machine. It
acceptsinputs and gives outputs tovarious
parts throughout the machine.
B. CONTROL PANEL
(NON-MICROPROCESSOR)
On models without microprocessors, a timer
is used to set a specific time. Most non-
microprocessor machines are built with dual
timers, a 60 minute dry timer and a 15 minute
cool down timer. The temperature selector
switch selects the “Hi,” “Perm Press,” or “Lo
Temp.” The “Push to Start” relay activates
the machine which starts the drying cycle.
C. CONTROL BOX
Opening the computer panel will reveal the control box. Inside
the control box are connectors for various harnesses traveling
throughout the machine. Located on the back of the control
panel is the computer.

11
D. HSI (HOT SURFACE IGNITION) MODULE
(Gas Models ONLY)
The HSI (Hot Surface Ignition) system consists of a
microprocessor (computer) based control module,
along with an ignitor/flame-probe assembly. This
control utilizes a 24 V carbide ignitor and a rectified
flame sensor/probe signal to locally control ALL basic
functions in the gas burner.
E. GAS BURNER ASSEMBLY
Gas heated dryers are equipped with
a gas burner assembly consisting of
four (4) burner tubes, gas valve, HSI
ignitor, sail switch, and hi-limit
thermostat. The inlet piping enters
through the rear of the dryer on the
left hand side (viewing from the front)
and runs to the front of the dryer where
the gas valve is located.
F. DRIVE MOTOR
The T.E.F.C. (Totally Enclosed, Fan-Cooled) drive
motor is located approximately lower center of the dryer.
It sits on an adjustable base so that the motor can be
easily adjusted to the left or right, up or down. The
drive motor is a 1 HP (0.75 kw) motor and operates on
208 to 460 volts, 3-phase (3ø), 50/60 Hz.

12
G. BLOWER MOTOR and IMPELLOR (GAS and STEAM)
The impellor is shaft driven. The blower motor
drives the shaft on which the impellor is
mounted. This enables the impellor to run at a
higher RPM, thereby producing a higher
airflow. (CFM).
H. IDLER ASSEMBLY
(Viewing from the rear of the dryer.)
The idler assembly is located approximately
on the lower center of the dryer. The idler
assembly consists of two (2) idler pulleys, the
small and large pulleys. The idler’s main
purpose is to reduce the speed and increase
torqueprovided to the tumbler (basket)bearing.
Also, at the idler assembly, belt tension can be
adjusted.
I. TUMBLER (BASKET) BEARING
and PULLEYARRANGEMENT
The tumbler (basket) bearing and pulley
arrangement is located (viewing from the rear
of the dryer) approximately at the upper center
of the dryer. The arrangement consists of a
pulley and two (2) bearings which serve to
drive, adjust, and support the tumbler (basket).

13
J. TUMBLER (BASKET)
The tumbler (basket) consists of four (4) ribs and four
(4) perforated panels, along with a front and back, which
are screwed together as an assembly. The tumbler
(basket) also consists of tie rods, which support the
tumbler (basket) from the front to back. The tumbler
(basket) support is used to mate the tumbler (basket)
to the drive system in the rear.
K. MAIN DOOR SWITCH
The main door switch is located in the main door hinge block. When the main
door opens, the switch will also open, preventing the dryer from operating. The
main door switch is a safety device and should never be disabled.
L. SAIL SWITCH (Gas Models ONLY)
The sail switch is located on the front of the
burner box. A sail switch consists of a round
damper plate on a lever arm which is in contact
with an electric switch. When the air blower
comes on, it draws air through the gas burner.
This creates a negative pressure inside the
burner box, and this negative pressure pulls in
the round damper and activates the sail switch.
If there is improper airflow, the damper will
not pull in, preventing the burner from starting.
Improper airflow can be caused by improperly designed exhaust ducting where the duct run is too long or has too
many sharp bends in it. It can also be caused by a lack of make-up air.

14
M. HI-LIMIT (Gas Models ONLY)
A hi-limit thermostat is located at the burner. This is a manual
reset disc-type thermostat set at 330º F (166º C). If the flame in
the burner should get too hot, this thermostat will shut off the burner.
This is generally caused by low airflow through the dryer.
N. AUTOMATIC RESET THERMOSTAT
This is located inside the dryer in the lint compartment
above the lint drawer. This thermostat senses the
heated air after it has passed through the tumbler
(basket). If the air temperature gets too hot, the
thermostat will shut off the burner. The dryer will not
run until the air temperature cools down. At this time,
the thermostat will reset. Tumbler (basket) and blower
will run, but the dryer will not heat.
O. LINT DRAWER
The lint drawer is a pullout type and is located at
the bottom of the dryer in the lint compartment.
Simply grab the lint drawer handle, slide out the
drawer, brush off the lint, and slide the drawer back
in. The lint screen must be kept clean in order for
the dryer to operate properly and efficiently.

15
P. LINT DRAWER SWITCH
The lint drawer switch is located in the lint compartment and attached to the
side of the lint drawer track. The lint drawer switch insures that the dryer will
operate only when the lint drawer is completely closed. This is a safety device
and should never be disabled.
Q. STEAM DAMPER SYSTEM
The newest type system is called the steam
damper. It is shown to the right and it uses a
piston with compressed air to open and close the
steam damper which in turn allows the air to flow
either through the coil for heat, or under the coil
for cool down. Air supply is 80 PSI +/- 10 PSI
(5.51 bars +/- 0.69 bars).
R. COMPRESSED AIR REQUIREMENTS
The model ML-170 requires an external supply of air (2.5
cfm @ 80 PSI [0.07 cmm @ 5.51 bars]) on the steam
models the air is necessary to operate the damper system.
On both steam, as well as the gas model, the air is
necessary/required for the blower air jet operation...to
clean lint from the impellor/fan (squirrel cage type).
S. TEMPERATURE SENSOR BRACKET
(NON-COMPUTER)
The non-computer temperature sensor bracket consists of four
(4) thermostats. Three (3) of them are the certain temperatures
that the machine should cycle on and off at. The fourth one is
the 225º F (107º C), safety tumbler (basket) hi-limit that should
only react when it sensors an over heat condition exceeding
225º F (107º C).

16
SECTION V
SERVICING
INTRODUCTION
ALL electrical and mechanical service or repairs should be made with the electrical power to the dryer
disconnected (power off).
WARNING: PERSONAL INJURY COULD RESULT.
The information provided in this section should not be misconstrued as a device for use by an untrained person
making repairs. Service work should be performed by competent technicians in accordance with local, state,
and federal codes.
When contacting the factory for assistance, always have the dryer model and serial numbers available.
CAUTION: Observe ALL safety precautions displayed on the dryer or specified in this manual before
and while making repairs.
Before considering replacement, make sure thatALL connectors are in place and making proper contact.
A. COMPUTER CONTROLS
To Replace Computer
1. Disconnect electrical power to the dryer.
2. Disconnect main power harness along with
the three (3) other connectors located on
the computer board, from rear of computer
by squeezing locking tab and pulling
connector straight back.
3. Disconnect the “green” ground wire from the computer and the wire connected to the air jet spade.
4. Disconnect keyboard (touchpad) ribbon from the computer.
5. Remove the two (2) Phillips screws securing the computer to the sheet metal control panel. Remove the
board by pulling the other two (2) corners off the clinch studs.
6. Install new computer by reversing this procedure.
7. When replacing the computer, the “A” and “B” factors must be reprogrammed. (Refer to “Computer
Operator’s Manual” for details.)
NOTE: The “A” and “B” factors are printed on a label located on the rear of the control panel (refer to
illustration).