A walk-in freezer that will not freeze is warm because cooling has stopped, ice has blocked the coil, the door or gasket leaks, or the refrigerant side is failing. Check for ice, a running outdoor unit and a tight door, and protect frozen stock. Freezers have extra parts, such as heaters and heated drains, that a cooler does not.
Freezers run near zero degrees Fahrenheit, so a small failure quickly shows up as soft ice cream, slushy packages or frost on boxes. A freezer has all the parts of a cooler plus defrost heaters, a heated drain line and often a heated door frame. That means more chances for a quiet fault, and a warm freezer can also be a symptom of an iced coil, not a dead compressor.
First look
- Read the temperature two ways. The controller and a separate thermometer. If they disagree, one may be wrong.
- Look at the coil. A block of ice or thick frost is the most common reason a freezer will not hold temperature.
- Listen for the fans and the outdoor unit. Are both running?
- Check the door. Closed, latched and sealed? A freezing door frame or torn gasket lets in humid air.
- Look at the stock. Overloading or boxes blocking the coil restrict airflow.
Causes, from most to least common
| Cause | Clues |
|---|---|
| Iced coil from a defrost fault | Solid ice on the coil, weak airflow, outdoor unit running |
| Door or gasket leak | Frost near the door, ice on the floor at the threshold, drafts |
| Failed evaporator fan | Silent fan, ice around one end of the coil |
| Outdoor unit not running | Compressor silent or humming, condenser fans off |
| Frozen drain | Water and ice in the pan and on the floor |
| Low refrigerant | Bubbles in the sight glass, oil at a joint, long run time |
| Controller or sensor drift | Display disagrees with a separate thermometer |
| Too much heat load | Warm product loaded, door open often, box undersized for the use |
What is different about a freezer
- Defrost is heater-based. A burned-out heater, a stuck timer or a failed termination switch lets ice build.
- The drain has a heater. Without it, water freezes in the line and backs up.
- The door frame is heated. A dead heater freezes the gasket to the frame.
- Loads are colder and less forgiving. Frozen product tolerates little warming.
Read the freezing up and defrost repair page for how those parts fail.
Protecting frozen food
Keep the door shut and check the product with a probe, not just the air. FDA guidance says a full freezer keeps its temperature for about 48 hours if the door stays closed, and about 24 hours if it is half full. It also says food that still has ice crystals or is at 40 degrees or below can be refrozen. A walk-in freezer is larger and better insulated than a household one, and inspectors decide what applies to a permit, so use the food-safety guide and follow your health department's direction.
What a technician does
- Thaws the coil safely and clears the drain.
- Tests the defrost timer, heaters, termination and fan-delay switches.
- Checks the evaporator and condenser fans.
- Reads pressures, superheat and the sight glass.
- Tests the door, gasket and frame heater.
- Compares the controller to an independent thermometer.
- Reviews the defrost schedule against real usage.
What to tell them
Give the temperature, how long it has been warm, whether there is ice on the coil, whether the fans and the outdoor unit are running, and how the freezer is used (storage only, or opened often). Add anything that changed just before it started, such as a delivery, a storm or a power blip.
For a warm cooler instead of a freezer, see walk-in cooler not cooling. If the outdoor unit is the suspect, the compressor and refrigerant page covers it, and the troubleshooting guide ties the checks together.
Questions about a warm freezer
Is a warm freezer always a compressor problem?
No. Ice on the coil, a dead fan or a leaking door produce the same symptom. Check those first.
Should I turn the temperature setting lower?
Not until you know the cause. A colder setting cannot fix an iced coil or a stopped compressor.
Can I move food to a cooler until it is fixed?
Frozen food warmed in a cooler starts to thaw. Use another freezer if one is available. Otherwise use insulated coolers with dry ice or ice packs, and treat the food according to how warm it got.