Whirlpool WED90HEFC W10240504 - Page 17

FOR SERVICE TECHNICIAN'S USE ONLY 7. Reassemble all parts and panels. 8. Plug in dryer or reconnect power. 9. Perform steps under "Install Diagnostics", page 7, 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 19. If the thermal fuse is OK, go to step 4. 4. Perform TEST #4c: Thermal Cut-Off on page 19. If the thermal cut-off is OK, go to step 5. 5. Locate the high limit thermostat (see figure 11, page 16). Measure the continuity through it by connecting the meter probes to the red and black 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 19. 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 7, to verify repair. Heat will not shut off: ALL DRYERS: 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. Refer to "Outlet Thermistor Resistance" table on page 18 for temperatures and their 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. 4. 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. Unplug dryer or disconnect power. With a voltmeter set to AC, connect voltmeter to terminals 1 & 2 for heater relay. Plug in dryer or reconnect power. Measure the voltage across terminals 1 & 2.  If voltage is present (~240VAC for electric, ~120VAC for gas), the relay is open and working normally.  If little or no voltage is present, the relay is closed and heater is activated. Unplug dryer or disconnect power and 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 7, to verify repair. TEST #4a: Thermistors NOTE: Refer to strip circuit on page 23 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 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 on page 18 gives temperatures and their associated resistance values. DO NOT REMOVE OR DESTROY PAGE 17