Whirlpool WFW3090GW, Service Manual, Page: 25 / 70

DIAGNOSTICS & TROUBLESHOOTING
Whirlpool Compact Front Load Washer
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2-9
For Service Technician Use Only
FAULT/ERROR CODES (Continued)
Icon Display Text Display Explanation and Recommended Procedure
F20
ACU Failure (Or Heater Failure)
The ACU has detected that the main or heater relay has a short or open circuit,
or that the heater has an open circuit.
Possible Causes
• Verify that the heater is OK by checking the resistance of the heater
connections (L1 and N), and then checking the resistance of the heater (L1
and N). If the heater has reduced resistance of L1 or N, replace the heater
and run the Service Test Cycle. If the heater has an open circuit, replace the
heater and the ACU.
• Check the connections on the heater and ACU and check the wires. If the
heater and wires are OK, replace the ACU.
F21
User Interface Communication Error
If the communication between the user interface module and the ACU is
disturbed, this error code will be displayed.
Possible Causes
• Check the wiring connection to the user interface.
• Check the user interface.
• Check the ACU (see TEST #1: ACU Power Check, page 3-4).
F24
Overflow Failure
If the ACU has read an overflow level on the pressure sensor, the drain pump
is turned on for one minute. The wash cycle will continue. The overflow failure
condition is reached if the overflow signal is detected five times in the same
wash cycle. In an overflow condition, the door will remain locked and the drain
pump will run intermittently.
Possible Causes
• Wash cycle with high water level was used with too many items/garments.
• Make sure that the drain hose is not plugged or kinked.
• Check the wire harness connections to the drain pump, pressure sensor, and
ACU.
• Make sure that the inlet valve is shutting off properly.
• Check the drain pump filter for foreign objects and clean, if necessary.
• Check for drain pump failure.
• Check the pressure sensor for proper operation.
F26
Pump Driver Failure
If, during the wash cycle, the ACU detects that the pump triac is defective, it will
display this error code.
Possible Causes
• Run the Service Test Cycle to check the ACU. If the failure occurs, replace the
ACU.
• Check the drain pump.
• Check the drain pump resistance (resistance too low can cause overcurrent
of drain pump, damaging the pump driver).
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