Freezer not freezing after a power outage: what to check and what to throw away

The power is back on, the lights are working, but the freezer is not freezing. Ice cream is soft, the ice trays are slush and there is water pooling at the bottom. This is a common call after a long outage, a storm or a stretch of load shedding. Sometimes the freezer just needs time. Sometimes the outage has exposed a fault that was waiting to happen. Here is how to tell which one you are dealing with.

Give it time first, but not too much

A freezer that has warmed up needs hours to pull back down to minus 18 degrees. If it was off for a long time and is full of warm food, it can take half a day or more. After about six to eight hours with the compressor running steadily, the freezer should be clearly colder. If it is still not freezing, or the compressor is not running at all, something else is wrong.

The common reasons it will not recover

1. The compressor does not restart

When power returns, the pressures inside the sealed system may not have settled, and a compressor that is already tired can fail to start. You might hear a click every few minutes with no hum. A worn start relay or overload protector is the most frequent culprit and is a quick repair. A seized compressor is more serious.

2. A surge or a rapid on-off cycle damaged a component

Power often comes back in a burst, with a surge and a few brief cuts. That can damage the control board on newer freezers, the thermostat or the compressor windings. If the freezer stopped working at the exact moment the power returned, a surge is a likely cause.

3. The freezer thawed and then refroze its own ice

If a lot of ice melted and then refroze around the evaporator, it can block the airflow or the drain. The freezer is running, but the cold air cannot circulate. Switching it off and defrosting it completely, with the door open and towels on the floor, often fixes this. If the ice comes back, the defrost system needs attention.

4. Something simple was knocked

During a power cut people open the freezer to check on things, and the door does not always close properly afterwards. A door left ajar by a few millimetres will stop a freezer from ever getting cold. Check the door seals, the drawers and the shelves to make sure nothing is holding the door open.

Is the food safe?

This is the question everyone asks, and the honest answer is that it depends on how warm the food got and for how long. As a general rule:

• A full freezer that stayed shut will keep food frozen for roughly a day or two, and a half-full one for about a day. Every time the door opens, that time shrinks.
• Food that still has ice crystals in it, or still feels as cold as a fridge, can generally be refrozen or cooked, though the quality may suffer.
• Meat, poultry, fish, dairy and cooked meals that have been above about 5 degrees for more than two hours should be thrown away.
• Never taste food to decide whether it is safe. If you are not sure, throw it out.
• Keep a thermometer in the freezer so you do not have to guess next time.

Protecting your freezer from the next outage

• Keep the freezer as full as you sensibly can. A full freezer holds its cold much longer.
• Freeze a few bottles of water and keep them in the gaps. They act as ice blocks.
• Resist opening the door during an outage.
• Plug the freezer into a surge protector, or use a plug-in delay unit that waits a few minutes before restoring power. Brief on-and-off cycles are hard on compressors.
• If your area has regular long outages, ask us about a backup power option for a commercial freezer.

When to call us

If the freezer has been running for eight hours and is still not freezing, if the compressor is silent or clicking, if you can see a thick layer of ice at the back, or if the freezer tripped your electrical board when the power returned, switch it off and call a technician. We can test the starting components and the controls, and tell you whether the fix is minor or whether the freezer has come to the end of its life. We work on household chest and upright freezers as well as commercial units.