Whirlpool CATALYST, Troubleshooting & Repair Manual, Page: 36 / 44

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Test #6 - Automatic Temperature Control (ATC) Test
This test checks the water inlet relays, the temperature sensor, and the control
board.
A: Test the fill valves
1. Check that the hot and cold water valves are working. Use the procedure in Test #2 .
Note: This test MUST be done with the Automatic Temperature Control off.
2. If working properly, go to B.
B: Test the temperature sensor
1. Turn on the Automatic Temperature
Control feature.
2. Set the water level setting to the “Low”
setting. Use the WASH/RINSE TEMP
selector button and set the Wash water
temperature to “Warm”.
3. Press the “Regular” or “Heavy Duty” cycle.
4. Press “Start”. After the tub fills, press the
“Stop/Pause” button. Measure the temper-
ature of the water. For the Warm setting,
the temperature range should be 90 - 110
degrees F which indicates proper operation.
5. If the temperature is not in this range,
check the Automatic Temperature Control
sensor as follows:
• Remove connector P5 from the microcomputer board.
• Measure the resistance between P5-5 and P5-4 in the connector. The resistance should be
between 74 k
Ω
and 24 k
Ω
. If not, check for continuity between the connector and the sensor.
If continuity is good, replace the temperature sensor/inlet valve assembly.
C: If system passes Steps A & B - Replace the control board.
Temperature
Degrees (F)
40
50
60
70
80
90
100
110
120
130
140
150
Resistance
(Ohms)
126k - 135k
97k - 102k
75k - 78k
58k - 61k
46k - 47k
36k - 37k
28k - 30k
23k - 24k
18k - 19k
15k - 16k
12k - 13k
10k - 11k
THERMISTOR RESISTANCE CHART