Roper Dryer Error Code F22: Thermistor Open Circuit... | appliancefaults.com

Technical Background:

The Roper dryer's Main Control Unit (MCU) constantly monitors the thermistor's resistance to determine the dryer's internal temperature. The thermistor is a temperature-sensitive resistor; its resistance changes with temperature. The MCU supplies a low DC voltage (typically 5V DC) to the thermistor circuit. An open circuit, indicated by the F22 error, means the MCU is not receiving the expected signal, suggesting a break in the circuit or a faulty thermistor.

Symptoms:

The homeowner reports the Roper dryer displays an F22 error code on the control panel. The dryer may not start, or it may start and then stop with the error code appearing shortly after. Clothes may not dry properly, or the dryer may overheat. There might be unusual noises coming from the dryer, or the dryer vent may be excessively hot.

Possible Causes:

Faulty thermistor
Open wiring harness to thermistor
Loose connection at the control board
Damaged control board
Clogged dryer vent restricting airflow
Incorrect thermistor reading due to surrounding heat

Solution:

1

Disconnect the dryer from the 120V AC power outlet.
2

Locate the thermistor, typically mounted near the blower housing inside the dryer cabinet. Remove the rear access panel using a 1/4-inch nut driver.
3

Visually inspect the wiring harness and connections leading to the thermistor for any signs of damage, corrosion, or loose connections.
4

Disconnect the thermistor wires and use a digital multimeter to measure its resistance. At room temperature (75°F), it should read approximately 10,000 ohms (10k ohms). An open circuit (OL reading) indicates a faulty thermistor.
5

If the thermistor tests bad, replace it with a new, OEM-approved Roper thermistor. Ensure correct polarity if applicable.
6

If the thermistor tests good, check the wiring harness continuity back to the control board using the multimeter. Look for any breaks or shorts in the wires.
7

Reassemble the dryer, reconnect the power, and test the dryer's operation. Monitor for the F22 error to reappear.

Safety Warning:

Always disconnect the power supply to the dryer before performing any repairs. Follow Lock Out Tag Out (LOTO) procedures. Capacitors in the control board can hold a dangerous electrical charge even after the power is disconnected. Use caution when working around electrical components.

Prevention:

Regularly clean the dryer vent and lint trap to ensure proper airflow. Avoid overloading the dryer, as this can lead to overheating and stress on the thermistor. Inspect the wiring harness periodically for any signs of damage.

Expert Tip:

On some Roper dryer models, you can access the diagnostic mode by pressing and holding the start button and another button (often the cycle select button) simultaneously for a few seconds. This may allow you to clear the error code after the repair is complete.

Frequently Asked Questions

•What is the typical resistance value of a good thermistor at different temperatures?

The resistance of a thermistor decreases as the temperature increases. A chart showing temperature vs. resistance values is needed to accurately determine if it is good. At 75F it is usually near 10k ohms.

•How do I check the wiring harness for continuity?

Using a multimeter set to the continuity setting, place one probe on one end of the wire and the other probe on the other end. If the multimeter beeps or shows a low resistance value (close to 0 ohms), the wire has continuity and is not broken. No beep or a high resistance indicates a break in the wire.

•Where is the dryer control board located, and how do I access it?

The dryer control board is typically located behind the control panel on the front of the dryer. To access it, you will usually need to remove the screws holding the control panel in place. Be careful when handling the control board to avoid damaging any of the components.

Roper Dryer Error Code F22: Thermistor Open Circuit Troubleshooting Guide

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the typical resistance value of a good thermistor at different temperatures?

•How do I check the wiring harness for continuity?

•Where is the dryer control board located, and how do I access it?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: