FOR SERVICE TECHNICIAN ONLY - DO NOT REMOVE OR DESTROY
PAGE 17
Inlet Thermistor (Amana Electric
Models Only)
The machine control electronics monitors the
inlet temperature using an inlet thermistor that
is part of the high limit thermostat assembly.
1.
Activate the Diagnostic Test Mode. See
procedure on page 1.
2.
If
f:24
or
f:25
is a displayed error in the
Diagnostic Test 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 21, and for inlet thermistor location, see
figure 10, page 15.
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 15, 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 by first removing
the toe panel. For thermal fuse location, see
figure 10, page 15.
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 by first removing
the toe panel.
3.
Using an ohmmeter, check the continuity
across the thermal cut-off. See figure 10, page
15, for location.
4.
If the ohmmeter indicates an open circuit,
perform the following:
ELECTRIC DRYER:
Replace the failed thermal
cut-off and high limit thermostat (inlet thermistor/
high limit thermostat assembly on Amana models).
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.
