Sub-Zero Refrigerator Error Code 10: Thermistor... | appliancefaults.com

Technical Background:

The main control unit (MCU) monitors the refrigerator compartment temperature via the thermistor. The thermistor is a variable resistor; its resistance changes with temperature. The MCU sends a small DC voltage (typically 5V DC) through the thermistor and measures the voltage drop. An Error Code 10 indicates the MCU is reading an out-of-range voltage.

Symptoms:

The homeowner observes that the refrigerator compartment is warmer than usual. Error Code 10 appears on the display. The compressor may run continuously, or not at all.

Possible Causes:

Open or shorted thermistor
Wiring harness damage
Loose wire connections
Faulty control board
Thermistor not properly seated in housing

Solution:

1

Unplug the Sub-Zero refrigerator from the 120V AC outlet and disconnect the water line.
2

Locate the refrigerator compartment thermistor. Typically located near the evaporator coil behind the rear panel.
3

Visually inspect the thermistor wiring harness for any signs of damage (cuts, breaks, or kinks).
4

Using a multimeter, measure the resistance of the thermistor. Refer to the Sub-Zero service manual for the correct resistance value at room temperature (approximately 77 degrees Fahrenheit).
5

If the resistance is significantly different, replace the thermistor with a new OEM part.
6

Check the wire connections at the control board using a 1/4-inch nut driver. Ensure they are secure.
7

If the wiring and thermistor are good, the control board may be faulty. Replace the control board.

Safety Warning:

Always disconnect power to the appliance before performing any repairs. Use Lock-Out/Tag-Out (LOTO) procedures to prevent accidental re-energizing of the circuit. This appliance operates on 120V AC; improper repairs can result in electric shock.

Prevention:

Regularly inspect the refrigerator compartment for proper cooling. Vacuum the condenser coils every 6 months to ensure efficient operation and prevent overheating of components. Check door seals regularly.

Expert Tip:

Some Sub-Zero models have a service mode that allows you to directly read the thermistor values. Refer to the service manual for the specific model to access service mode, usually a sequence of button presses (e.g., holding the “Door Alarm” and “Max Cool” buttons simultaneously for 5 seconds).

Frequently Asked Questions

•What is the typical resistance range for a Sub-Zero refrigerator thermistor at room temperature (77 degrees Fahrenheit)?

Typically between 5,000 and 10,000 ohms (5k to 10k ohms), but refer to the specific model's service manual for the exact value.

•Where is the control board located on a Sub-Zero refrigerator?

The location varies by model. Generally, it is located at the top, either behind the control panel or behind the top grill.

•If the thermistor tests good, what other components could cause Error Code 10?

A break in the wiring harness between the thermistor and the control board, or a faulty control board itself.

Sub-Zero Refrigerator Error Code 10: Thermistor Troubleshooting Guide

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the typical resistance range for a Sub-Zero refrigerator thermistor at room temperature (77 degrees Fahrenheit)?

•Where is the control board located on a Sub-Zero refrigerator?

•If the thermistor tests good, what other components could cause Error Code 10?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: