Sub-Zero Freezer Error Code EC06: Evaporator Thermistor... | appliancefaults.com

Technical Background:

The EC06 error code indicates that the main control unit (MCU) is detecting an abnormal resistance reading from the freezer evaporator thermistor. The MCU uses the thermistor's resistance to determine the freezer's evaporator coil temperature. If the resistance is outside the acceptable range, the MCU will trigger the EC06 error and may affect cooling performance. The thermistor acts as a variable resistor with a negative temperature coefficient (NTC); as temperature increases, resistance decreases. The MCU applies a small DC voltage (typically 5V DC) across the thermistor, and measures the resulting current to calculate the resistance. An open circuit results in a high voltage reading, while a short circuit results in a low voltage reading.

Symptoms:

The homeowner reports that the freezer temperature is fluctuating, the unit is struggling to maintain temperature, and the EC06 error code is displayed on the control panel.

Possible Causes:

Faulty evaporator thermistor
Wiring harness issue (open or shorted)
Loose connection at the thermistor or control board
Control board failure
Thermistor physically iced over
Excessive frost buildup impacting thermistor readings

Solution:

1

Disconnect power to the unit at the breaker panel.
2

Locate the freezer evaporator thermistor, usually behind the rear panel inside the freezer compartment.
3

Using a multimeter, measure the resistance of the thermistor at room temperature (approximately 77°F). Consult the Sub-Zero service manual for the correct resistance value for your model. It should be in the kilo-ohm range.
4

Inspect the wiring harness and connections for any signs of damage, corrosion, or looseness. Repair or replace as needed. Ensure good contact at the connector pins.
5

If the thermistor resistance is out of range, replace the thermistor. Use an OEM Sub-Zero thermistor.
6

Clear any frost or ice buildup around the evaporator coil and thermistor. Ensure proper defrost operation.
7

Reconnect power to the unit. If the EC06 error persists, the control board may be faulty and require replacement.

Safety Warning:

Always disconnect power to the Sub-Zero at the breaker panel before performing any repairs. Use proper Lock-Out/Tag-Out (LOTO) procedures. Some components operate at 120V AC and pose a risk of electric shock.

Prevention:

Regularly inspect the freezer for excessive frost buildup. Ensure the door seals are clean and in good condition to prevent air leaks. Schedule annual or bi-annual maintenance to check thermistor operation and defrost system efficiency.

Expert Tip:

After replacing the thermistor, initiate a manual defrost cycle to ensure proper operation of the defrost system. This can often be accomplished by pressing and holding specific buttons on the control panel simultaneously (refer to the service manual for the specific key combination for your model). This will help verify that the thermistor is reading correctly and that the defrost system is functioning as designed.

Follow-up Questions:
• How do I access the freezer evaporator thermistor on my specific Sub-Zero model?
• What is the correct resistance value for the freezer evaporator thermistor at 32°F?
• How do I test the defrost heater and defrost thermostat to ensure they are functioning correctly?

Frequently Asked Questions

•How do I access the freezer evaporator thermistor on my specific Sub-Zero model?

The location varies by model. Consult the service manual for exploded diagrams showing component locations. Generally, you'll need to remove the freezer's rear panel, which is typically held in place by screws. Be careful not to damage any wiring or refrigerant lines during disassembly.

•What is the correct resistance value for the freezer evaporator thermistor at 32°F?

The exact resistance value varies depending on the specific thermistor used in your Sub-Zero model. Refer to the service manual for the temperature/resistance chart for your specific model. However, a typical value is in the 8-12 kilo-ohm range at 32°F.

•How do I test the defrost heater and defrost thermostat to ensure they are functioning correctly?

To test the defrost heater, use a multimeter to check for continuity. Disconnect one wire from the heater before testing to isolate it. The defrost thermostat should be closed (continuity) at temperatures below its set point (typically around 40°F). Above the set point, it should be open (no continuity).

Sub-Zero Freezer Error Code EC06: Evaporator Thermistor Troubleshooting

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•How do I access the freezer evaporator thermistor on my specific Sub-Zero model?

•What is the correct resistance value for the freezer evaporator thermistor at 32°F?

•How do I test the defrost heater and defrost thermostat to ensure they are functioning correctly?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: