Maytag 111990" Automatic Dryers User manual

Maytag
111990" Automatic Dryers
Service Manual
16000132
Issued 1990
Revised 2/98

Contents
SECTION 1. ELECTRICAL TEST EQUIPMENT " 1-1
APPLIANCE TEST METER 1-1
CLAMP-ON AMMETER '. ....................... .. 1-3
MOTOR TEST CORD 1-4
VOLTAGE CHECKS 1-5
TEMPERATURE READINGS RANGE (50°F.
to 300°F.) 1-6
SECTION 2. ELECTRICAL -MECHANICAL TROUBLESHOOTING
2-1
WILL NOT RUN 2-1
WILL NOT DRY '2-2
WILL NOT SHUT OFF
,............................... 2-2
MISCELLANEOUS
,................................... 2-6
MICROPROCESSOR
BOARD CONTROL MODELS 2-7
DRYER (MICROPROCESSOR BOARD CONTROL)
2-11
FAULT CODE 2-15
SECTION 3. SERVICE PROCEDURES
3-1
ACCESS TO CONTROL PANEL COMPONENTS 3-1
CONTROL PANEL ASSEMBLY COMPONENTS 3-1
MICROPROCESSOR BOARD CONTROL 3-10
FRONT PANEL AND COMPONENTS 3-13
TUMBLER AND RELATED COMPONENTS 3-17
THERMOSTATS 3-24
BLOWER
3··27
DRIVE MOTOR AND IDLER ASSEMBLY ,........................ 3-28
HEATING ELEMENT
AND RELATED COMPONENTS -- ELECTRIC MODELS 3-31
GAS VALVE AND RELATED COMPONENTS 3-34
CABINET AND TOP COVER
3-41
SECTION 4. PRE-INSTALLATION CONSIDERATIONS 4-1
LOCATING DRYER 4-1
EXHAUSTING 4-2
ADJUSTING
MAIN BURNER 4-6
ELECTRICAL REQUIREMENTS 4-8
ELECTRICAL CONNECTIONS 4-10
A!?DITIONAL INFORMATION 4-12
PERSONAL SAFETY PRECAUTIONS
'.' . . .. 4-12
SECTION 5. GENERAL INFORMATION
5-1
HEAT SOURCE 5-1
MODEL CHART 5-2
SCHEMATICS 5-3
ED/GD401 1090 Contents

ED/GD401 1090 Contents
ii

INTRODUCTION
This service manual is intended to assist you in diagnosing conditions which may
develop. Electrical
component testing is for the most part, made with an appliance
test
meter and consists of checking for open or closed circuits. Mechanical checks
are made through sight and sound, along with the use of aclamp-on ammeter.
This manual is designed for the technician who is familiar with the operation and
construction of May tag products. Information contained in this manual is intended
for use by a qualified service technician, familiar with proper and safe procedures
to be followed when repairing an electrical appliance. All tests and repairs should
be performed by a qualified service technician equipped with proper tools and
measuring devices. All component replacements should be made by a qualified
service technician, using only MA yeOR replacement parts.
Improper assembly or adjustment may occur if service or repair is attempted by
persons other than qualified service technicians or if parts other than MA yeOR
replacement parts are used. Improper assembly or adjustment can cause haz-
ardous conditions.
There can be risk of injury or electrical shock while performing services or repairs.
Injury or electrical shock can be serious or even fatal.
The first and most important step of any service call is to accurately determine what
the
complaint is. This is best accomplished by questioning the customer, finding
out what the prodUct is or isn't doing and why they feel a problem exists.
Section 1covers Electrical Test Equipment. This sections also
covers general use
of
the equipment; an Appliance Test Meter, Clamp-On Ammeter and Motor Test
Cord.
Section 2
covers Electrical-Mechanical Troubleshooting and a list of possible com-
plaints. Find
the complaint which you feel best matches that provided by the cus-
tomer and turn to the appropriate page(s). You will find a list of possible electrical
and mechanical
problems for the complaint, which have been listed in there order
\
of:
1. Ease in checking.
2. Probability.
ED/GD401 1090 INTRODUCTION Iii

Systematically eliminating these possibilities will allow you to find and correct the
problem.
Section 3 covers Service Procedures. This section will provide information on
location of components, disassembly and/or reassembly procedures, the purpos,e
and/or function of the part and in some instances specific checks to be made.
Section 4 covers Pre-Installation Considerations. This provides information on
location and exhausting of dryer, main burner adjustment, electrical requirements
and connections.
Section 5 covers General Information. This section covers brief specifications,
cycle descriptions and schematics.
\ ....
ED/GD401 1090 INTRODUCTION iv

SECTION 1. ELECTRICAL TEST EQUIPMENT
The equipment required to service
May tag products depends largely upon
the condition encountered. Locating a
malfunction will often require the use of
electrical testing equipment such as:
•
Appliance Test Meter
• Clamp-on Ammeter
• Motor Test Cord
APPLIANCE TEST METER
Probably the easiest means of testing
electrical components is ~'continuity
testing" with an Appliance Test Meter.
Continuity is a complete or continuous
path from one point in an electrical
circuit to another point.
The
obvious advantages of being able
to check electrical components and cir-
cuits without power applied is one of
the features of the ohmmeter. Multiple
ranges allow accurate determination of
resistances of both single components
and entire circuit paths. Resistance is
measured in "ohms".
An Appliance Test Meter is a multi-
purpose tester combining an AC-DC
voltage tester with a multi-range
ohmmeter.
\
SF
2
APPLIANCE TEST METER
SET METER FOR USE AS FOLLOWS:
1. Calibrate meter by touching test
probes together and turning
adjusting dial until meter reads "0"
on the ohm scale. Recheck cali-
bration whenever adjusting dial for
ohms settings is changed. (Replace
battery
if adjustment will not bring
meter reading to "0".)
2. Select the scale most easily read
and place test
probes on respective
terminals. When checking aswitch,
the reading would normally be
either open or closed. A reading of
70 on the R x 10 scale would for
example be 700 ohms resistance.
ED/GD401 1090 SECTION
1. ELECTRICAL TEST EQUIPMENT 1-1

~f~
~.,~"] Q
CAUTION ---------------,
Always be sure the power has been
disconnected before making resist-
ance
measurements. Failure to do
so will result in damage to your
meter! Internal batteries provide all
the power needed to make resist-
ance checks. They
should be
checked at least once a
year and
replaced as needed.
For the most part, we will only be con-
cerned with continuity. Is there apath
or not? References are made between
a
"closed" (continuity) reading and an
"open" (no continuity) reading. One
note,
when you get an "open" reading,
try a higher resistance range (setting).
A
very high resistance appea~s as an
"open" on the lower ranges. For best
accuracy alw~ys "re-zero" meter when
changing ranges and/or the physical
position of the meter.
Continuity testing, as related to an elec-
\
tricarcomponent, is the check of a part
for an "open" or "closed" circuit.
Electrical components fall into two
general categories.
1. Loads- Devices that use or
consume electricity: Examples
ED/GD401 1090
would include drive motor, heating
elements, lamps,
timer and solenoid
coils.
2.
Switches -Devices that control the
supply of electricity to the load or
loads in a circuit. Examples include
door switches, timer contacts,
selector switch and relay contacts.
Continuity test of "load" devices will
show varying levels of resistance from
very low for some transformer and
motor windings to very high for some
timer motors and components on elec-
tronic control boards. Usually it is
more important to know if there is a
path
for current .flow through a device
(continuity) than to know the exact
resistance (ohms)
of the device.
Continuity tests of switches will show
virtually no resistance, even low values
indicates burned or dirty contacts in a
switch.
Continuity testing is a process of elimi-
nating those electrical components
involved in a given function of the
appliance, until the inoperative part is
found. By reviewing the list of possible
electrical problems under a given con-
dition, and then performing appropriate
continuity checks on the parts involved,
you should be able to locate the elec-
trical component which is inoperative.
When checking components or circuit
paths for continuity, external wiring
should be disconnected to eliminate
false readings through external paths.
Isolate what
you want to test.
The
following shows typical resistance
values for some of the components
found on May tag dryers.
Heating Element -- 10.23 ohms.
SECTION 1. ELECTRICAL TEST EQUIPMENT 1-2

Gas Valve
Disconnect radiant sensor and igniter
wires. Measure across igniter wires or
igniter plug from valve to get a resist-
ance value of -- 425-450 ohms.
Measure across sensor wires to get a
resistance
of -- 450-475 ohms.
Drive Motor
Red terminal to Gray terminal -- 1.5
ohms.
In order to measure the individual
windings the red and gray wires will
have to be pulled off of the start switch.
Run
winding only -- 2.25 ohms.
Start Winding only -- 3 ohms.
Glow Bar Igniter
Because of the make-up of the igniter,
the resistance will vary over a rather
wide range. Values from 180 ohms to
400
ohms would be typical with an
igniter at room temperature.
These values are provided so that you
may have an idea of the resistance that
you can see in testing. These resist-
ances
are not meant to be used as the
exact
values to determine whether a
t;omponent should be replaced. They
\
are provided so that you may have an
idea of the resistance that you can see
in
testing components.
EDIGD401 1090
CLAMP-ON AMMETER
Each circuit in an appliance has a
"normal" current draw which is an indi-
cation of the performance of that circuit.
Current draw levels, less than or more
than normal, give clues to malfunctions.
The clamp-on
ammeter measures these
currents without breaking the circuit by
measuring the strength of the magnetic
field developed around each conductor.
Current is read by separating the con-
ductors and clamping the jaws of the
ammeter around each conductor on
which current is to be read. Low
amperage readings indicate problems
such as damaged heating elements,
etc.
High amperage readings indicate
the unit being tested is operating under
an increased mechanical or electrical
load.
SECTION 1. ELECTRICAL TEST EQUIPMENT 1·3

Note: Overloads on a circuit breaker
or fuse can be traced to the product
being tested or the circuit breaker (or
fuse) by checking the product's current
draw. If the amperage reading is less
than the breaker reading, the breaker
or fuse box is at fault.
USE OF AMMETER ON DRYER
There are two currents of concern to us
in an
electric dryer; the heating
element current and the drive motor
current. These currents can be meas-
ured by use of a "split line cord" exten-
sion for the dryer cord or by attaching
the ammeter to the respective power
line wires at the dryer terminal block.
Current measured should be 21 amps
on the heating element side of the line,
24
amps on the drive motor side of the
line and 4 amps on the center or
neutral line.
A
\".
MOTOR TEST CORD
The motor test cord may be used. to
electrically check operation of the drive
motor while still installed in the unit.
Testing
of the motor in this manner
determines whether or not it will run
independently of other electrical com-
ponents.
Two test leads are required to check
operation of the drive motor. To check
the motor for running, hook up test
cord as shown.
WHORGY
OVERLOAD'- ,
PROTECTOR ( "
,\
START RUN'
\
I \
,START :AD
YEL 0RUN
0--- I
START Q . CENT. SWITCH
~~N 0----- -q-oBLK
BU .... ,', ... /
.......... __ ....
DRIVE MOTOR
Location of terminals on motor may vary from drawing.
ED/GD401 1090 SECTION 1. ELECTRICAL TEST EQUIPMENT 1-4