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What is Defrost Mode?

What is defrost mode cover

Modern air conditioners are equipped with many operating modes. These are all designed to ensure smooth and efficient operation throughout a variety of weather conditioners. But, what happens when the outdoor ambient temperature is very low? What happens when there is ice on the outdoor unit? When this occurs, chances are the air conditioner will go into defrost mode. But, what exactly is defrost mode?

What is defrost mode?

Defrost mode is when the outdoor unit gets too cold and sometimes the coil will be covered in ice. The unit cannot operate when there is ice on the coil, and it must defrost the ice before continuing to provide conditioned air. How can you tell if your air conditioner is in defrost mode?

To defrost the outdoor coil a number of things will occur. The indoor unit will stop blowing air, depending on the brand an indication of the defrost cycle will appear on the air conditioning controller. Often a whooshing noise will be heard at the outdoor unit, the outdoor fans will start and stop erratically, the ice on the external air conditioning coil will melt and fall away. This means a large puddle of water can be created around the outdoor unit.  Often, the appearance of smoke will occur at the external outdoor unit, this is steam. Everything we have mentioned above is normal for an air conditioner going through defrost mode.

air con with ice

How long does this take?

The entire defrost cycle may take 10 to 45 minutes, depending on the air conditioning brand, and the outside ambient temperature. Sadly, during the defrost mode the air conditioner will stop blowing hot air. In-fact, it may blow cold air. The main thing for the user is to not panic, leave the system on and do not adjust the temperature, fan speed, zones or operating mode.

When the system recognises the defrost mode is complete the system will automatically start and return to the heating function Defrost often occurs early in the morning on low ambient temperature days.

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