Whirlpool Dryer Various Test Procedures - Part 2
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,
Thermal fuse,
High limit thermostat,
Gas burner assembly,
Centrifugal switch,
Exhaust thermistor,
Machine control electronics,
Gas supply.
Dryer does not heat:
1. Unplug dryer or disconnect power.
2. Remove the back panel to access the
thermal components.
3. Perform TEST #4b. If the thermal fuse is
OK, go to step 4.
4. Perform TEST #4c. If the thermal cut-off
is OK, go to step 5.
5. Locate the high limit thermostat. Measure the continuity through it
by connecting the meter probes on the
red wire and blue wire terminals.
If there is an open circuit, replace the
high limit thermostat and thermal cutoff.
Otherwise, go to step 6.
6. Perform TEST #4d. If this is OK, replace
the machine control electronics.
Heat will not shut off:
1. Unplug dryer or disconnect power.
2. Access the machine control electronics,
remove the P14 connector, then measure
the resistance between P14-3 (red-white
wire) and P14-6 (red-white wire) at the
connector.
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 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.
If wire connections are OK, check 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:
TEMP
SETTING
HEAT TURNS
OFF*
HEAT TURNS
ON
High
155° ± 5°F
(68°± 3°C)
10–15°F
(6–8°C)
below the
heat turn off
temperature
Medium
140° ± 5°F
(60°± 3°C)
10–15°F
(6–8°C)
below the
heat turn off
temperature
Low
125° ± 5°F
(52°± 3°C)
10–15°F
(6–8°C)
below the
heat turn off
temperature
Extra Low
105° ± 5°F
(41°± 3°C)
10–15°F
(6–8°C)
below the
heat turn off
temperature
The measured overshoot using the glass
bulb thermometer in the exhaust outlet can
be 30°F (17°C) higher.
5. If the exhaust temperature is not within
specified limits, or you have come here
from step 3, remove the P14 connector,
then measure the resistance between
P14-3 (red-white wire) and P14-6 (redwhite
wire) at the connector.
If the resistance is OK, check P14-3
and P14-6 to machine ground.
If resistance is greater than 0 (zero),
replace wiring harness.
NOTE: All thermistor resistance measurements
must be made while dryer is
disconnected from power.
The following table gives temperatures
and ranges for the associated thermistor
resistance values.
Temp
F C
Res
kΩ
Temp
F C
Res
kΩ
50° (10°)
19.0 -22.0
80° (27°)
8.5-10.5
60° (16°)
14.8-16.8
90° (32°)
6.8-8.8
70° (21°)
11.5-13.5
100° (38°)
5.0-7.0
If the thermistor resistance does not
agree with table, replace the exhaust
thermistor.
If the thermistor resistance checks
agree with the measurements in the
table, replace the machine control
electronics.
TEST #4b Thermal Fuse
The thermal fuse is wired in series with the
dryer drive motor.
1. Unplug dryer or disconnect power.
2. Access the thermal fuse by first removing
the back panel.
3. Using an ohmmeter, check the continuity
across the thermal fuse.
If the ohmmeter indicates an open circuit,
replace the failed thermal fuse.
TEST #4c Thermal Cut-Off
If the dryer does not produce heat, check the
status of the thermal cut-off.
1. Unplug dryer or disconnect power.
2. Access the thermal cut-off by first removing
the back panel. .
3. Using an ohmmeter, check the continuity
across the thermal cut-off.
If the ohmmeter indicates an open circuit,
replace the failed thermal cut-off
and high limit thermostat. In addition,
check for blocked or improper exhaust
system.
TEST #4d Gas Valve
1. Unplug dryer or disconnect power.
2. Access the gas valve by removing the
front panel and drum assembly.
3. Use an ohmmeter to determine if a gas
valve coil has failed. Remove harness
plugs. Measure resistance across terminals.
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