Why do Air Conditioning Units Freeze?

At Enercell Air Conditioning, our experienced local HVAC technicians have seen it all when it comes to poorly maintained, manufactured, and serviced AC units. The summers in Sydney can be brutal and unrelenting, and you need your air conditioner to work flawlessly when the hottest months of the year hit their peak. If your air conditioner blower fan is putting out warm air, it’s possible that your air conditioner unit is freezing up. If you don’t fix it quickly, you could be in for some massive electric bills and a busted compressor. So what’s going inside a frozen air conditioner? We’ll explain below.

How does an air conditioner work?

The air conditioner takes the heat out of the house and transfers it outside while it cools the air inside of the building. Your AC can not only change the temperature of your home, it can also change the humidity level inside and the general quality of your air. The AC unit pumps the air through the ductwork.

For split systems, the compressor inside the AC unit condenses and circulates a material called refrigerant through the outside AC unit. The refrigerant changes from a gas to a liquid during this process through refrigerant lines inside the unit. The liquid refrigerant is pushed through an indoor evaporator coil, which is sometimes referred to as a cooling compartment. The AC unit inside the building has a blower fan which circulates the inside air to pass over the evaporator fins. These fins exchange thermal energy.

At this point in the process, the refrigerant turns into a vapor and removes heat from the air. Then, the air is cooled and circulated back through the house as cold air. The condenser outside turns the refrigerant vapor into a liquid again, removing heat. When the refrigerant fluid leaves to evaporate again, it will do so in the form of a cold gas. The process starts all over again until the building is lowered to the desired temperature that you’ve set on your thermostat.

Why do Air Conditioning Unites Freeze | Enercell Air Conditioning

What’s going on in a frozen AC unit?

When air conditioning units freeze, there could be many things going on inside the unit. You could have a refrigerant leak, low refrigerant levels, a dirty air filter, or a dirty coil. The air flow inside the unit could be blocked by dust and debris, too. AC units need the air flowing correctly to keep the evaporator coils at the right temperature.

The AC unit needs to pull warm air from the building to keep the coil cold, but above freezing temperature. When the unit can’t pull in air, the coils will freeze before any condensed water can work its way into the drain pan. If your unit freezes, there are a couple of things you can do to get the air blowing again.

Dirty air filters are some of the biggest culprits when an AC freezes. If you notice your AC unit is blowing warm air, you’ll want to check the air filter first. If that’s not the issue, then move on to the air registers. Look for debris and dust. These parts of the AC unit are easy to clean, and if they are beyond saving, they aren’t too expensive to replace, either. Also, low refrigerant levels might be the cause of your frozen AC unit. A faulty fan may also prevent air from circulating. Our local HVAC techs can recharge your refrigerant levels and replace a faulty blower fan. Chances are, your frozen AC unit does not need to be replaced, but just needs a quick tune-up.

Drainage issues can also block the mechanics and cause the air conditioning units to freeze. In some cases, the thermostat is the issue. During the cooling process, the unit will condense the refrigerant water vapor into a liquid, which will drain outside. But if the refrigerant coils freeze, the ice blocks the hole that the liquid will drain from. The AC will still run if this happens, but it will blow warm air into the house, and it will also guzzle electricity. Twigs, dirt, and other debris can block the drain hole, too. Failing to fix a frozen AC quickly enough will eventually damage the compressor. The compressor is the most expensive part of an AC unit.

For professional air con repairs and air conditioning installations Sydney wide, call Enercell today on 1800 849 018.


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