FOR SERVICE TECHNICIAN’S USE ONLY
PART NO. W10054150
TECH SHEET - DO NOT DISCARD
PAGE 8
TEST #4
Heater
This test is performed when either of the
following situations occur:
✔
Dryer does not heat
✔
Heat will not shut off
This test checks the components making up
the heating circuit. The following items are
part of this system:
–
Harness/
connection
–
Heater relay
–
Thermal cut-off
–
Inlet thermistor/
high limit
thermostat
–
Heat element
assembly
–
Centrifugal switch
–
Exhaust thermistor
–
Machine control
electronics. See
ESD information,
page 1.
–
User interface
assembly
Dryer does not heat:
Locate the components using figure 2,
page 6; and figure 9, below.
SINGLE ELEMENT MODEL:
1.
Unplug dryer or disconnect power.
2.
Remove the back panel to access the
thermal components. See Removing the
Back Panel, page 12.
3.
Using an ohmmeter and referring to the
appropriate wiring diagram and strip
circuit, pages 4 and 5, measure the
resistance from the red wire terminal at
the thermal cut-off to the red wire terminal
at the heater.
➔
If the resistance is about 10 ohms, go
to step 5.
➔
If an open circuit is detected, go to
step 4.
4.
Visually check the wire connections to the
thermal cut-off, high limit thermostat, and
heater. If connections look good, check
for continuity across each of these
components.
➔
Replace the heater if it is electrically
open.
➔
Replace both the thermal cut-off and
high limit thermostat if either one is
electrically open.
5.
If no open circuit is detected, remove the
P4 connector, then measure the
resistance between P4-3 (red wire) and
P4-6 (red wire) at the connector. See
figure 15, page 11 for connector location;
and Accessing & Removing the
Electronic Assemblies, page 11.
➔
If 5–15 k ohms are measured, replace
the machine control electronics.
➔
If the resistance is less than 1 k ohm,
replace the thermistor.
DUAL ELEMENT MODEL:
1.
Unplug dryer or disconnect power.
2.
Remove the back panel to access the
thermal components. See Removing the
Back Panel, page 12.
3.
Measure the resistance across the high
limit thermostat.
➔
If an open circuit is not detected, go to
step 4.
➔
If an open circuit is detected, replace
both the thermal cut-off and the inlet
thermistor/high limit thermostat.
4.
Measure the resistance across the
thermal cut-off
➔
If an open circuit is not detected, go to
step 5.
➔
If an open circuit is detected, replace
both the thermal cut-off and the inlet
thermistor/high limit thermostat.
5.
Measure the resistance between the red
wires at the heater.
➔
If an open circuit is not detected, go to
step 7.
➔
If an open circuit is detected, go to
step 6.
6.
Visually check the wire connections to
the heater. If the connections look good,
replace the heater.
7.
Measure the resistance at the heater
between the violet wire and the red wire
terminals.
➔
If an open circuit is not detected, go to
step 9.
➔
If an open circuit is detected, go to
step 8.
8.
Visually check the wire connections to
the heater. If the connections look good,
replace the heater assembly.
9.
If no open circuit is detected, remove the
P4 connector, then measure the
resistance between P4-3 (red wire) and
P4-6 (red wire) at the connector. See
figure 15, page 11 for connector location;
and Accessing & Removing the
Electronic Assemblies, page 11.
➔
If 5–15 k ohms are measured, replace
the machine control electronics.
➔
If the resistance is less than 1 k ohm,
replace the exhaust thermistor.
Heat will not shut off:
1.
Unplug dryer or disconnect power.
2.
Access the machine control electronics,
remove the P4 connector, then measure
the resistance between P4-3 (red wire)
and P4-6 (red wire) at the connector. See
figure 15, page 11 for connector location;
and Accessing & Removing the
Electronic Assemblies, page 11.
➔
If 5–15 k ohms are measured, replace
the machine control electronics.
➔
If the resistance is greater than
20 k ohms, replace the exhaust
thermistor.
TEST #4a
Thermistors
EXHAUST THERMISTOR
The machine control electronics monitors the
exhaust temperature using the exhaust
thermistor, and cycles the heater relay on
and off to maintain the desired temperature.
Begin with an empty dryer and a clean lint
screen.
1.
Plug in dryer or reconnect power.
2.
Start the Timed Dry cycle.
3.
If after 60 seconds,
F-22
or
F-23
flashes
in the display and the dryer shuts off, the
thermistor or wire harness is either open
or shorted.
➔
Unplug dryer or disconnect power.
➔
Check wire connections at the
machine control electronics and
thermistor. See Accessing & Removing
the Electronic Assemblies, page 11;
and for thermistor location, figure 9.
➔
If wire connections are OK, check the
exhaust thermistor resistance per
step 5.
4.
If
F-22
or
F-23
does not flash in the
display, the connections to the thermistor
are good. Therefore, check the exhaust
temperature value at any or all of the
temperature levels in question, using the
Timed Dry cycle, and the following
process:
Hold a glass bulb thermometer capable
of reading from 90° to 180°F (32° to 82°C)
in the center of the exhaust outlet. The
correct exhaust temperatures are as
follows:
Thermistor
4 Duct
Screws
Thermal
Cut-Off (TCO)
Heat
Element
Inlet Thermistor/
High Limit
Thermostat
Harness
Connection
Thermal
Fuse
Sensor
Wires
Drum
Light
Lint Duct
Figure 9.
Thermal components, viewed
from rear.
