Test #12B: Dry Temperature Sensor (Ntc) - Whirlpool WFC8090GX Service Manual

COMPONENT TESTING
WARNING
Electrical Shock Hazard
Disconnect power before servicing.
Replace all parts and panels before operating.
Failure to do so can result in death or
electrical shock.
TEST #12b: DRY TEMPERATURE
SENSOR (NTC)
The ACU monitors the heater channel temperature using the
dry NTC, and cycles the dry heater relay on and off to maintain
the desired temperature.
NOTE: Begin with an empty washer/dryer at ambient
temperature and a clean lint screen.
1. Unplug washer/dryer or disconnect power.
2. Gently lay washer/dryer on its right side to access the
ACU. Remove AC shield and ACU cover.
3. Remove connector J14 from the ACU and measure the
resistance between J14-1 and J14-2 at the connector. The
following table gives temperatures and their associated
resistance values.
THERMISTOR SENSOR RESISTANCE
Approx. Temperature
F° C°
-4 -20
14 -10
32 0
59 15
DRY TEMPERATURE SENSOR (NTC)
ACU
3-20 Whirlpool Smart All-In-One Washer & Dryer
n
For Service Technician Use Only
Approx. Resistance
(KW)
197.3
111.6
65.5
31.5
J14-2
+5 VDC
DRY TEMPERATURE SENSOR
Figure 2 - Dry Temperature Sensor (NTC) Strip Circuit
Approx. Temperature
77
86
104
122
140
158
176
194
212
248
302
¾ If the resistance is infinite or close to zero, go to step 4.
¾ If it is within range, go to step 7.
4. Remove the top panel to access the heater channel
assembly.
5. Disconnect the dry temperature sensor connector from
the NTC. See Figure 1.
6. Using an ohmmeter, measure the resistance across pins 1
and 2 of the dry temperature sensor.
¾ If the resistance is within the specified range, the
sensor is good; replace the main harness.
¾ If the resistance is far out of range or open, replace the
temperature sensor.
7. If the preceding steps did not correct the dry temperature
sensor problem, replace the ACU.
Dry Temp
Sensor (NTC)
Figure 1 - Dry NTC Location on Heater Channel Assembly
77°F (25°C) = 20.0 k ohms
T
THERMISTOR SENSOR RESISTANCE
Approx. Resistance
25
30
40
50
60
70
80
90
100
120
150
HEATER CHANNEL ASS'Y
ACU
J14-1
DRY NTC
20.0
16.1
10.6
7.1
4.9
3.4
2.4
1.8
1.3
0.7
0.3
TCO's