GE Café Dishwasher: Rhythmic Humming Noise During Dry... | appliancefaults.com

Technical Background:

The main control unit (MCU) manages the Dry Boost cycle by activating a heating element and a fan motor. Voltage is supplied to these components via relays on the MCU. The diverter valve directs water flow during the wash and rinse cycles. Problems within these voltage paths can cause unusual noises.

Symptoms:

US homeowner reports a rhythmic humming noise originating from the GE Café dishwasher during the Dry Boost cycle, questioning if it's normal.

Possible Causes:

Stuck or partially blocked diverter valve.
Failing circulation pump motor.
Obstruction in the air duct of the Dry Boost system.
Faulty relay on the main control board (MCU) causing voltage fluctuations to the fan motor.
Vibration from a loose fan blade or housing.

Solution:

1

Disconnect power to the dishwasher at the breaker panel (LOTO).
2

Access the dishwasher's lower access panel using a 1/4-inch nut driver.
3

Check the circulation pump for any visible obstructions. Remove the lower spray arm and check the pump inlet for debris.
4

Inspect the diverter valve operation. Manually actuate the diverter valve and check for smooth movement. If sticking, it may need replacement.
5

Using a multimeter, check the voltage supply to the Dry Boost fan motor during operation. Should read approximately 120V AC. Erratic voltage readings may indicate a failing relay on the main control board.
6

Examine the fan motor for any physical damage or loose blades. Replace if necessary.
7

If the voltage and fan motor appear normal, inspect the air duct for blockages or obstructions.

Safety Warning:

Always disconnect power to the appliance at the breaker panel before performing any diagnostic or repair procedures. Lock Out/Tag Out (LOTO) procedures must be followed to prevent accidental power restoration. High voltage is present within the dishwasher; exercise caution.

Prevention:

Run a dishwasher cleaner monthly. Regularly check and clean the spray arms and filter to prevent debris buildup that can cause pump and diverter valve issues. Avoid overloading the dishwasher to ensure proper water circulation.

Expert Tip:

Some GE Café dishwashers have a service mode. Enter the service mode by pressing and holding the “Start” and “Cycle Select” buttons simultaneously for approximately 5 seconds. Refer to the service manual for detailed testing and calibration procedures.

Frequently Asked Questions

•What is the resistance range I should expect from the Dry Boost fan motor?

The resistance of the Dry Boost fan motor should typically be between 40 and 60 ohms. An open or shorted reading indicates a faulty motor.

•How do I properly test the diverter valve for proper operation?

Using a multimeter, check the continuity of the diverter valve solenoid coil. Also, visually inspect the valve for free movement. If there's no continuity, the solenoid is likely bad. If the valve is sticking, clean or replace the valve.

•Where is the location of the thermistor in the Dry Boost system and how do I test it?

The thermistor is typically located near the heating element in the Dry Boost system. Disconnect the power and then disconnect the thermistor. Use a multimeter to measure its resistance. At room temperature (77°F), it should read around 12k ohms. The resistance should change with temperature variations. If it reads open or shorted, it needs replacement.

GE Café Dishwasher: Rhythmic Humming Noise During Dry Boost - Troubleshooting

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the resistance range I should expect from the Dry Boost fan motor?

•How do I properly test the diverter valve for proper operation?

•Where is the location of the thermistor in the Dry Boost system and how do I test it?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: