Sub Zero Freezer Not Cooling? Discover Why and Fix It Now!

March 26, 2024

Sub Zero Freezer Not Cooling? Expert Spring Fixes Here | Sub-Zero Certified Repair
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When your refrigerator or Sub Zero freezer is not cooling, it can disrupt your routine and lead to food spoilage. Understanding the underlying causes can help you address these issues promptly. Below, we explore the most common reasons for cooling problems in your refrigerator or Sub Zero freezer and provide detailed solutions for each one.

Power Supply Issues

A reliable power supply is fundamental for your refrigerator or freezer to function. If there’s no power, the cooling system can’t operate.


  • Check the Plug and Outlet: Ensure the appliance is properly plugged into a functioning electrical outlet. Test the outlet with another device to confirm it’s delivering power.
  • Inspect the Circuit Breaker: Look at your home’s circuit breaker panel for any tripped breakers or blown fuses. Reset the breaker or replace the fuse if necessary.
  • Examine the Power Cord: Check the power cord for any signs of damage. A frayed or broken cord should be replaced to avoid electrical hazards.

Incorrect Temperature Settings

Inappropriate thermostat settings can prevent your refrigerator or freezer from maintaining the desired temperature, leading to inadequate cooling.


  • Adjust the Thermostat: Make sure the thermostat is set to the recommended temperature—37°F (3°C) for refrigerators and 0°F (-18°C) for freezers. Allow several hours for the changes to take effect.
  • Recalibrate or Replace the Thermostat: If adjusting the thermostat doesn’t resolve the issue, it might be faulty. Consider recalibrating it according to the manufacturer’s instructions or replacing it if necessary.

Dirty or Blocked Condenser Coils

Condenser coils release heat from the appliance. If they are dirty or blocked, they can’t effectively dissipate heat, leading to your Sub Zero freezer not cooling as it should.


  • Clean the Coils: Unplug the refrigerator or freezer and use a vacuum or a soft brush to clean the coils, which are usually located at the back or underneath the appliance. This should be done at least twice a year.
  • Ensure Proper Airflow: Make sure there’s adequate space around the unit for airflow. It should be placed a few inches away from walls or other obstructions to allow proper ventilation.

Condenser Fan Motor Failure

The condenser fan motor is responsible for drawing air over the condenser coils to cool them. If this fan stops working, the coils won’t cool effectively, impacting the appliance’s ability to maintain low temperatures.


  • Check for Obstructions: Inspect the fan blades and area around the condenser fan for debris or obstructions that might be hindering its operation. Clean away any debris and ensure the fan can spin freely.
  • Test the Fan Motor: If the fan isn’t operating, test the motor to see if it needs replacement. This can be done using a multimeter to check for continuity.

Evaporator Fan Motor Issues

The evaporator fan circulates cool air throughout the refrigerator or freezer. If it fails, cold air distribution is disrupted, causing uneven or insufficient cooling.


  • Listen for the Fan: Open the freezer door and listen for the evaporator fan running. If you don’t hear it, it might be defective.
  • Inspect and Replace the Motor: Access the fan motor behind the freezer’s back panel and check for any visible damage. If the motor is faulty, replacing it can restore proper air circulation.

Faulty Start Relay

The start relay provides the initial power to start the compressor. A faulty relay can prevent the compressor from running, which means the appliance won’t cool.


  • Test the Start Relay: Locate the relay on the compressor and gently shake it. A rattling sound indicates it may be defective. You can also test it with a multimeter.
  • Replace the Relay: If the relay is found to be faulty, replacing it is a straightforward fix that can restore the compressor’s functionality.

Compressor Problems

The compressor is critical for circulating refrigerant throughout the cooling system. If it fails, the entire cooling process is compromised, leading to your Sub Zero freezer not cooling.


  • Listen for the Compressor: Check if the compressor is running. If it’s silent or making unusual noises, it might be malfunctioning.
  • Consult a Professional: Compressor issues are complex and often expensive to fix. It’s advisable to consult a professional Sub Zero Freezer Repair Service expert to diagnose and repair or replace the compressor if necessary.

Frost Build-up on Evaporator Coils

Frost or ice accumulation on the evaporator coils can block airflow and reduce the cooling efficiency of your appliance.


  • Manually Defrost: Turn off the refrigerator or freezer and let the ice melt naturally. This can temporarily resolve the cooling issue.
  • Check the Defrost System: Inspect the defrost timer, heater, and thermostat. If any of these components are faulty, they may need to be replaced to prevent future frost buildup.

Damaged Door Seal or Gasket

A damaged door seal allows warm air to enter the refrigerator or freezer, making it difficult for the appliance to maintain the correct temperature.


  • Inspect the Gasket: Look for any cracks, tears, or warping in the door gasket. Close the door on a piece of paper; if it slips out easily, the seal is likely defective.
  • Replace the Gasket: Replace any worn or damaged gaskets to ensure a tight seal. This helps maintain efficient cooling and prevents warm air from entering.

Preventive Maintenance Tips

  • Regularly Clean Components: Keep the condenser coils and fans clean to ensure efficient operation.
  • Ensure Proper Placement: Maintain adequate space around the appliance for proper airflow and avoid placing it near heat sources.
  • Avoid Overloading: Don’t overload the refrigerator or freezer, as this can hinder air circulation and put extra strain on the cooling system.
  • Check Door Seals: Regularly inspect door seals and gaskets for damage and replace them as needed.
  • Schedule Professional Maintenance: Periodic maintenance by a qualified technician can help identify and fix potential issues before they become major problems.


Sub Zero freezers not cooling can be a significant hassle, leading to spoiled food and potential health risks. By understanding common cooling issues and their solutions, you can quickly address and resolve these problems, ensuring your appliance runs efficiently. Regular maintenance and timely repairs like our Sub Zero Freezer Repairs in Alsip are key to keeping your unit in top condition. If you encounter a problem beyond your expertise, don’t hesitate to seek professional assistance.

Contact Sub Zero Certified Repair today for expert troubleshooting and reliable repairs. We’re dedicated to getting your appliance back to optimal performance, so your food stays fresh and your life runs smoothly.

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