Whirlpool Washer Service Manual page 16

FOR SERVICE TECHNICIAN'S USE ONLY
 If little or no voltage is present, the relay
is closed and heater is activated. Replace
the CCU.
7. Unplug dryer or disconnect power.
8. Reassemble all parts and panels.
9. Plug in dryer or reconnect power.
10. Perform the "Quick Diagnostic Test"
through Service Diagnostics to verify repair.
TEST #4a: Thermistors
NOTE: Refer to strip circuit on page 22 to
diagnose outlet and inlet temperature thermistors.
Outlet (Exhaust) Thermistor
The CCU monitors the exhaust temperature
using the outlet thermistor, and cycles the
heater relay on and off to maintain the desired
temperature. NOTE: Begin with an empty dryer
and a clean lint screen.
3 Quick Check: Exhaust thermistor readings
in °F, °C, and resistance are provided
in "Service Diagnostics ➔ Component
Activation ➔ Exhaust Thermistor."
1. Unplug dryer or disconnect power.
2. Remove top panel to access the machine
electronics.
3. Remove connector P14 from the CCU
and measure the resistance between P14-3
and P14-6 at the connector. The following
table gives temperatures and their associated
resistance values.
NOTE: All thermistor resistance measurements
must be made while dryer is unplugged and
connector removed from CCU.
OUTLET THERMISTOR RESISTANCE
RES.
TEMP.
RANGE
°F (°C)
k ohms
50° (10°) 19.0–22.0
60° (16°) 14.8–16.8
70° (21°) 11.5–13.5
 If the resistance is OK, the outlet thermistor
is good. Proceed to step 4.
 If the thermistor resistance does not agree
with the table, replace the outlet thermistor.
4. Check P14-3 and P14-6 to dryer cabinet
ground. If either pin indicates continuity
to ground (short), replace wiring harness;
otherwise, proceed to step 5.
PAGE 16
RES.
TEMP.
RANGE
°F (°C)
k ohms
80° (27°) 8.5–10.5
90° (32°) 6.8–8.8
100° (38°) 5.0–7.0
5. If the preceding steps did not correct the
problem, replace the CCU.
Temperature Levels Incorrect – If no error code
is displayed and the connections to the thermistor
are good, check the exhaust temperature value
at any or all of the temperature levels in question,
using the Timed Dry cycle. IMPORTANT: Be
sure EcoBoost (if available) is turned OFF before
testing.
1. Remove load from dryer and disconnect
external vent.
2. Plug in dryer or reconnect power.
3. Run a TIMED DRY cycle of at least 2
minutes in duration. Select High, Medium
High, Medium, Low, or Extra Low. Turn off
EcoBoost.
4. Using a calibrated temperature probe,
take a temperature measurement in the
center of the exhaust outlet. The correct
exhaust temperatures are as follows:
EXHAUST TEMPERATURES
TEMPERATURE HEAT TURNS OFF*
SETTING °F (°C)
High 155° ± 5° (68° ± 3°)
Medium High 150° ± 5° (65° ± 3°)
Medium 140° ± 5° (60° ± 3°)
Low 125° ± 5° (52° ± 3°)
Extra Low 105° ± 5° (41° ± 3°)
 If the temperature is not reached within
~7 minutes, check voltage level and vent
blockage, and then retest.
 If the temperature probe does not agree
with temperature setting, replace the outlet
thermistor.
 If the temperature probe confirms the
temperature setting, retest at a different
temperature setting.
5. If the preceding steps did not correct the
problem, replace the CCU.
Inlet Thermistor
The CCU monitors the inlet temperature using
the inlet thermistor. The inlet thermistor (along
with the outlet thermistor) is used to detect
air flow, and assists in calculating load size.
NOTE: On the electric dryer, the inlet thermistor
is part of the high thermostat assembly (see
figures 20a & 20b). On the gas dryer, the inlet
thermistor is located below the CCU bracket
at the drum inlet duct (see figure 28, page 27).
DO NOT REMOVE OR DESTROY
HEAT TURNS ON
°F (°C)
10–15° (6–8°)
below the
heat turn off
temperature