Troubleshooting guide

FOR SERVICE TECHNICIAN ONLY - DO NOT REMOVE OR DESTROY
PAGE 14
Inlet Thermistor (Electric Dryers)
The machine control electronics monitors the
inlet temperature using an inlet thermistor that
is part of the high limit thermostat assembly.
1. Activate the DiagnosticTest Mode. See
procedure on page 1.
2. If f:24 or f:25 is a displayed error in the
DiagnosticTest Mode, the inlet thermistor or wire
harness is either open or shorted.

Unplug dryer or disconnect power.

Check wire connections at the machine
control electronics and inlet thermistor. See
Accessing & Removing the Electronic Assemblies,
page 17, and for inlet thermistor location, see
figure 10, page 12.

If wire connections are good, remove
the wires from the inlet thermistor/high limit
thermostat assembly and replace the assembly.

Plug in dryer or reconnect power.
3. If f:24 or f:25 is not an error that is displayed
in the Diagnostic Test Mode, the connections to
the thermistor are good.Therefore, check the
thermistor’s resistance value, using the following
process:

Unplug dryer or disconnect power.

Access the heater assembly.

Hold a glass bulb thermometer capable of
reading from 68° to 176°F (20° to 80°C) in the
heater assembly.

Check the resistance of the inlet thermistor.
See figure 10, page 12, for location.
The following table shows the resistance
values that should be observed for the various
temperatures at the heater assembly.
INLET THERMISTOR RESISTANCE
Res. Res.
Temp Range Temp Range
°F (°C) kΩ °F (°C) kΩ
68° (20°) 61.2–63.7 131° (55°) 14.6–15.3
77° (25°) 49.0–51.0 140° (60°) 12.1–12.8
86° (30°) 39.5–41.1 149° (65°) 10.2–10.7
95° (35°) 32.0–33.3 158° (70°) 8.5–9.0
104° (40°) 26.1–27.2 167° (75°) 7.2–7.6
113° (45°) 21.4–22.3 176° (80°) 6.1–6.5
122° (50°) 17.6–18.5

If the thermistor resistance does not agree
with the measurements in the table, replace the
inlet thermistor/high limit thermostat assembly.

If the thermistor resistance agrees with the
measurements in the table, replace the machine
control electronics.
TEST #4b Thermal Fuse
ELECTRIC DRYER: The thermal fuse is wired
in series with the dryer drive motor.
GAS DRYER:
The thermal fuse is wired in series
with the dryer gas valve.
ALL DRYERS:
1. Unplug dryer or disconnect power.
2. Access the thermal fuse. For thermal fuse
location, see figure 10, page 12.
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.
3. Using an ohmmeter, check the continuity
across the thermal cut-off.See figure 10, page
12, for location.
4. If the ohmmeter indicates an open circuit,
perform the following:
ELECTRIC DRYER:
Replace the failed thermal
cut-off and inlet thermistor/high limit thermostat
assembly.In addition,check for blocked or
improper exhaust system, or failed heat element.
GAS DRYER:
Replace the failed thermal cut-off
and high limit thermostat. In addition, check for
blocked or improper exhaust system.