PAGE 15
FOR SERVICE TECHNICIAN’S USE ONLY
DO NOT REMOVE OR DES
TROY
5.
If no open circuit is detected, remove the
P4
connector from the CCU and measure the outlet
thermistor resistance between P4-3 and P4-6
at the connector. Refer to “Outlet Thermistor
Resistance” table on page 16 for temperatures
and the associated values.
If resistance corresponds to the temperature,
the outlet thermistor is good. Go to step 6.
If the thermistor resistance does not agree
with the table, replace the outlet thermistor.
6.
If the preceding steps did not correct the
problem and L1 and L2 were both detected,
replace the CCU. If L2 was not detected, suspect
the centrifugal switch before replacing the CCU.
7.
Reassemble all parts and panels.
8.
Plug in dryer or reconnect power.
9.
Perform steps under “Install Diagnostics”,
page 5, to verify repair.
GAS DRYER ONLY:
1.
Verify the gas supply to the dryer is turned on.
2.
Unplug dryer or disconnect power.
3.
Perform TEST #4b: Thermal Fuse on page
17. If the thermal fuse is OK, go to step 4.
4.
Perform TEST #4c: Thermal Cut-Off on page
17. If the thermal cut-off is OK, go to step 5.
5.
Locate the high limit thermostat (see
Figure 12b, page 14). Measure the continuity
through it by connecting the meter probes
to the black and blue wire terminals.
If there is an open circuit, replace both the
high limit thermostat and the thermal cut-off.
Otherwise, go to step 6.
6.
Perform TEST #4d: Gas Valve on page
17. If the gas valve is OK, go to step 7.
7.
If the preceding steps did not correct
the problem, suspect the centrifugal switch
before replacing the CCU.
8.
Reassemble all parts and panels.
9.
Plug in dryer or reconnect power.
10.
Perform steps under “Install Diagnostics”,
page 5, to verify repair.
Heat will not shut off:
ALL DRYERS:
1.
Unplug dryer or disconnect power.
2.
Remove console to access the CCU
and User Interface (UI).
3.
Remove connector
P4/P14
from the CCU
and measure the resistance between P4/P14-3
and P4/P14-6 at the connector. Refer to “Outlet
Thermistor Resistance” table on page 16 for
temperatures and the associated values.
If the resistance corresponds to the
temperature, the outlet thermistor is good.
If the thermistor resistance does not agree
with the table, replace the outlet thermistor;
if open, repair as necessary.
4.
ELECTRIC DRYER ONLY: Check heater
coil for a short to ground (usually inside the
heater box). Repair or replace if necessary.
5.
Plug in dryer or reconnect power.
6.
Run an “
air only
” “
timed dry”
cycle (no
heat). Check heater relay output on CCU (see
page 9). With a voltmeter set to
AC
, measure
the voltage across heater relay terminals 1 & 2.
If voltage is present (~240V AC for electric,
~120V AC for gas), the relay is open and
working normally.
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 steps under “Install Diagnostics”,
page 5, 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.
1.
Unplug dryer or disconnect power.
2.
Remove console to access the CCU and
User Interface (UI).
3.
Remove connector
P4/P14
from the CCU
and measure the resistance between P4/P14-3
and P4/P14-6 at the connector. The following
table on page 16 gives temperatures and the
associated resistance values.
NOTE:
All thermistor resistance measurements
must be made while dryer is unplugged and
connector removed from CCU.
