Whirlpool 72974 Scheda tecnica - Pagina 2

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TECH SHEET - DO NOT DISCARD
Fabric Care/Temperature
Switch Test
Orange
Remove the wires
from the switch to
complete this test.
Reference contact
continuity with Pins
White
1 and 2 to Pin 4.
Reference contact
continuity with Pin 3 to Pin 5.
Fabric Care Switch Test
CONTACTS
SWITCH
POSITION
3
2
1
9 O'clock
O
O
O
10 O'clock
O
O
X
12 O'clock
O
X
O
2 O'clock
O
X
X
3 O'clock
X
O
O
O = OPEN
X = CLOSED
Wrinkle Guard Switch (On/Off)
Test
Remove the wires
Gray
from the switch to
complete this test.
Reference contact
continuity to
White
Pin 4 (White).
Wrinkle Guard Switch Table
SWITCH
CONTACTS
POSITION
11 O'clock
Open
1 O'clock
Closed
"End of Cycle" Signal Switch
Test
White/Black
Remove the wires
from the switch to
complete this test.
Reference contact
continuity to
White
Pin 4 (White).
Signal Switch Table
CONTACTS
SWITCH
POSITION
1
2
10 O'clock
O
O
12 O'clock
X
O
2 O'clock
O
X
O = OPEN X = CLOSED
Heater Box High-Limit
Thermostat Test
Remove the thermistor from the fan housing
and plug the hole. Protect the thermistor and
leads from grounding against any metal parts.
See Figure 1. Completely block the exhaust
outlet. Turn dryer on and allow the high-limit
thermostat to cycle once, then measure the
time elapsed until the high-limit thermostat
FOR SERVICE TECHNICIAN'S USE ONLY
Violet
Tan
Flame
Sensor
1
2
3
4
5
FABRIC
FUNCTION
NO HEAT
EXTRA LOW
MEDIUM
MEDIUM HIGH
HIGH
Thermal
Fuse
trips. It should trip between 21 and 38 seconds.
1
IMPORTANT: Be sure to reinstall the thermis-
4
tor after testing thermostat.
WRINKLE
GUARD
Thermal Fuse Test
A thermal fuse is used on this model. The ther-
mal fuse is wired in series with the dryer gas
valve. If the thermal fuse opens, power is shut
off to the gas valve. (Centrifugal switch in mo-
FUNCTION
tor also opens heater circuit.)
Wrinkle Guard OFF
Once the thermal fuse has opened, it must be
Wrinkle Guard ON
replaced. Check for failed thermistor or other
cause of failure. Replace failed parts. See
Figure 1.
Tan/White
Thermistor Test or Dryer
Beeps 3 Times When Push To
1
2
Start (PTS) Pressed
4
An electronic temperature sensor called a
SIGNAL
thermistor is used in this model in place of an
operating thermostat. The Even Heat Control
monitors the exhaust temperature using the
thermistor and cycles the heater relay on and
off to maintain the desired temperature.
Procedure
FUNCTION
Begin with an empty dryer and a clean lint
OFF
screen.
LOW End
1. Set the following configuration:
of Cycle Signal
Timer Dial -
HIGH End
Fabric Care/Temperature switch -
of Cycle Signal
COTTON / TOWELS HIGH
Wrinkle Guard switch - OFF
Signal switch - HIGH
Door - must be closed
2. Press the Push To Start (PTS) switch.
a. If you hear three short beeps and the
dryer shuts off after several seconds, the
thermistor or wire harness is either
shorted or open. Check wire connec-
tions at Even Heat Control and thermis-
tor. If wiring is functional, replace the
thermistor: Unplug the dryer and remove
High Limit
Thermostat
Thermistor
Figure 1
TIMED DRY
the front toe panel. Remove the two
wires and replace the thermistor as
shown in Figure 1.
b. If the dryer appears to operate correctly,
proceed to step 3.
3. Remove exhaust vent and start the dryer.
a. Turn Fabric Care/Temperature switch to
desired temperature to be tested, and
select 20 minutes on the Timed Dry dial.
Hold a glass bulb thermometer capable of
reading from 90°F to 180°F in the center of
the exhaust outlet. Measure exhaust tem-
peratures with heater off and on. The
correct exhaust temperatures are as
follows:
FABRIC CARE/
HEAT
TEMP. SWITCH
TURNS
SETTING
OFF
COTTON / TOWELS
150° ± 10°F
HIGH
NORMAL
140° ± 10°F
MEDIUM HIGH
PERM PRESS / CASUAL
125° ± 10°F
MEDIUM
ULTRA DELICATE
115° ± 10°F
EXTRA LOW
b. If the exhaust temperature is not within
specified limits, check the resistance of
the thermistor.
THERMISTOR RESISTANCE
TEMP . ° F RES. K Ω TEMP . ° F RES. K Ω
50°
19.9
100°
60°
15.3
110°
70°
11.9
120°
80°
9.2
130°
90°
7.4
140°
c. If the thermistor resistance checks within
normal limits, replace the Even Heat
Control Assembly.
Gas Valve Test
Using an ohmmeter, it is
possible to determine if
either gas valve coil has
failed. Remove harness
plugs. Measure resis-
tance across terminals
indicated in the chart
below. Readings should
match those shown in
chart. If not, replace coil.
IMPORTANT:
Be sure all harness
TERMINALS RESISTANCE
wires are looped
back through the
1 to 2
strain relief after
1 to 3
checking or
4 to 5
replacing coils.

TROUBLESHOOTING

PROBLEM: Dryer Will Not Run
(Refer to Motor Strip Circuit, page 6)
If the motor will not start, check the following:
–
LINE VOLTAGE
– HARNESS/CONNECTION
– MOTOR RELAY
– PUSH TO START (PTS) SWITCH
PART NO. 3979119
PAGE 2
HEAT
TURNS
ON
10° - 15°F
below heat off
5.7
4.7
3.7
3.1
2.5
1365Ω ± 25
560Ω ± 25
1220Ω ± 50