Amana Dryer Error Code F28: Moisture Sensor Fault... | appliancefaults.com

Technical Background:

The F28 error code on an Amana dryer indicates a fault in the moisture sensing circuit. The Main Control Unit (MCU) monitors the resistance between the moisture sensor bars in the drum. When the MCU detects an abnormal resistance value (open or shorted circuit), it triggers the F28 error. The voltage path typically involves a 5V DC signal from the MCU to the sensor, with a return signal indicating the moisture level.

Symptoms:

The dryer displays error code F28. The dryer may stop mid-cycle or not start at all. Clothes may not dry properly, even after extended drying times.

Possible Causes:

Open or shorted moisture sensor.
Wiring harness issue between moisture sensor and control board.
Faulty control board (MCU).
Poor drum grounding.
Lint buildup on the moisture sensor bars.

Solution:

1

Disconnect power to the dryer at the breaker panel.
2

Locate the moisture sensor bars inside the dryer drum, typically near the lint filter.
3

Inspect the wiring harness connected to the moisture sensor for any signs of damage, such as cuts, crimps, or loose connections.
4

Using a multimeter, test the resistance of the moisture sensor. A normal reading is typically between 10k and 50k ohms depending on moisture levels; consult the tech sheet for exact specs.
5

Clean the moisture sensor bars with a soft cloth and isopropyl alcohol to remove any lint or residue.
6

Check the drum grounding. Ensure the metal drum has a solid electrical connection to the dryer chassis. Test with a multimeter from the drum to the metal chassis, should read near 0 ohms. Clean grounding point if needed.
7

If the wiring and sensor are good, the control board (MCU) may be faulty. Replace the control board with a new or refurbished part.
8

After repairs, run a test cycle to confirm the F28 error is resolved.

Safety Warning:

Disconnect power to the dryer at the breaker panel before performing any repairs. This dryer operates on 240V AC. Improper handling can result in severe electrical shock or death. Always Lock Out Tag Out (LOTO) the breaker.

Prevention:

Regularly clean the lint filter after each load. Periodically inspect and clean the moisture sensor bars inside the dryer drum with a soft cloth and isopropyl alcohol.

Expert Tip:

Many Amana dryers have a diagnostic mode. Consult the service manual for instructions on entering diagnostic mode and retrieving error history. This can help pinpoint intermittent sensor issues. On some models, holding down the start button and the cycle select button simultaneously for 3 seconds will enter diagnostic mode.

Frequently Asked Questions

•What is the correct resistance value for the moisture sensor on my specific Amana dryer model?

The resistance value varies by model. Consult the dryer's service manual or technical data sheet for the specific resistance range.

•How do I properly clean the moisture sensor bars?

Use a soft cloth lightly dampened with isopropyl alcohol. Gently wipe the bars to remove lint and residue. Ensure the bars are completely dry before operating the dryer.

•If the moisture sensor and wiring are good, is there anything else besides the control board that could cause this error?

While less common, a faulty thermistor can sometimes interfere with the moisture sensing circuit. Check the thermistor's resistance and compare it to the value specified in the service manual. Also, inspect the drum slides and felt seals. Excessive wear can create a gap between the drum and the chassis, causing grounding issues.

Amana Dryer Error Code F28: Moisture Sensor Fault Troubleshooting

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the correct resistance value for the moisture sensor on my specific Amana dryer model?

•How do I properly clean the moisture sensor bars?

•If the moisture sensor and wiring are good, is there anything else besides the control board that could cause this error?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: