Topics:

• How to manually defrost the freezer section
• Ice or frost building up inside top area of freezer section
• Ice on back wall of the freezer
• What can cause frost in the freezer of a Sub-Zero unit?
• Freezer shelves, drawers, bins have condensation or fog or are freezing over
• Freezer basket or drawer rails frozen over
• Moisture in freezer

Cause:

• Freezer door left ajar
• Freezer drain tube frozen
• Torn gasket
• Defrost element failure
• Ice maker not filling properly

Troubleshooting:

For any frost or ice build-up in a Sub-Zero freezer, follow these steps:

1. Verify the door was not left ajar for a period of time.
   • Some condensation inside a unit or on the shelving or drawers is normal if the door is opened or left open for a period of time.
   • In warm climates, this will be noticeable more quickly.
   • Keep the door closed, and fogging will resolve on its own.
2. Remove anything blocking the door from closing.
   • If a drawer could be blocking the door, extend the drawer out fully and close it again. This can help the drawer realign and slide all the way in more easily.
   • If the door does not stay closed after removing obstructions, refer to Sub-Zero Door Difficult to Close.
3. Inspect door gaskets for tears, rips, or dry rot. Replace if damaged.
   • Genuine parts for Sub-Zero, Wolf, and Cove products are available by calling the Factory Certified Parts Distributor in your area. Use locator to find the Parts Distributor in your area.
     
4. Verify the freezer basket retainers are not broken for Classic (formerly Built-In) and 600 Series units.
5. Clean the Condenser if not done in the last three months.
6. Check setpoint temperatures for the compartment.
   • On an electronic control panel, the recommended freezer temperature is 0°F.
   • For a dial control, set the dial between 4 and 6. 1 is warmest, and 10 is coldest.
7. If the drain tube is frozen, clean the drain tube. See:
   • Freezer Drain Tube Cleaning
   • 600 Series Freezer Drain Tube Cleaning SWS# 1810000
   • 500 or 600 Series Freezer Drain Tube Cleaning
   • Classic (Formerly Built-In) Series, 700 Series, 400 Series, 648PRO Drain Clogged
8. Defrost the freezer. See Manually Defrost a Sub-Zero for instructions.
9. Wait 24 hours for the unit to return to normal temperatures and frost to clear after correcting any of the above.
10. If these troubleshooting steps do not resolve the issue, service is necessary to expertly diagnose and repair the product. Contact Factory Certified Service to schedule an appointment for repair.

Additional Resources

Moisture and Ice

• Excessive Moisture or Condensation
• Ice Block or Water Leaking in Ice Maker Area
• Ice or Frost on Back Wall of Refrigerator

Doors and Drawers

• Sub-Zero Door Gasket Replacement
• Sub-Zero Door Difficult to Close
• Sub-Zero Basket or Drawer Glides Squeak
  
• 600 and Classic Series Over Under Freezer Basket Retainers

Temperature

• Measuring Temperatures in a Refrigerator or Freezer
• Freezer Burn on Food