Whirlpool Duet Sport WED8300SW Manual page 83

Heat will not shut off:
1. Unplug dryer or disconnect power.
2. Access the machine control electronics,
and measure the resistance between P14-3
(red-white wire) and P14-6 (red-white wire).
See Accessing & Removing the Electronic
Assemblies.
• If 5–15 k ohms are measured, replace
the machine control electronics.
• If the resistance is greater than 20 kΩ,
replace the thermistor.
TEST #3a Thermistor Test
The machine control electronics monitors the
exhaust temperature using the 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, and for thermistor location
see Figure 11.
• If wire connections are good, remove
the two wires from the thermistor and
replace the thermistor. See Figure 11.
• Plug in dryer or reconnect power.
4. If F-22 or F-23 does not flash in the display,
the connections to the thermistor are good.
Therefore, check the thermistor's resistance
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:
EXHAUST TEMPERATURES
TEMPERATURE
SETTING
High
Medium
Low
Extra Low
* 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, check the resistance of the
thermistor.
NOTE: All thermistor resistance measurements
must be made while dryer is disconnected
from power.
The table below gives the resistance values
that should be observed for the various
temperature settings.
TEMP.
SETTING TEMPERATURE
155° ± 5°F
High
(68° ± 3°C)
140° ± 5°F
Medium
(60° ± 3°C)
125° ± 5°F
Low
(52° ± 3°C)
Extra
115° ± 5°F
Low
(46° ± 3°C)
If needed, the following table gives tempera-
tures and their associated resistance values.
THERMISTOR RESISTANCE
TEMP.
°F (°C)
50° (10°)
60° (16°)
70° (21°)
6-11
HEAT TURNS HEAT TURNS
OFF* ON
155° ± 5°F
(68° ± 3°C)
10–15°F
140° ± 5°F
(6–8°C)
(60° ± 3°C)
below the
125° ± 5°F
heat turn off
(52° ± 3°C)
temperature
115° ± 5°F
(46° ± 3°C)
Thermistor resistance
value at heater
shutoff (digital or
analog meter) k
2.1 1.7
2.8 2.3
3.8 3.1
4.7 3.8
RES. TEMP. RES.
k Ω °F (°C) k Ω
19.9 80° (27°) 9.2
15.3 90° (32°) 7.4
11.9 100° (38°) 5.7