Why Do Air Conditioners Freeze Up?

May 24, 2021

If you have seen your air conditioner freeze, you have probably noticed how you get less air coming from your system. What causes the unit to freeze, and what can you do about it when it happens? Reed Service Company in Beaumont has put together this simple guide to help you through this perplexing problem.

How an AC Creates Cold Air

The idea of your air conditioner creating cold air is a bit of a misconception. Yes, the air coming out of your vents is cold. However, the AC unit is actually removing heat from the air moving through your system.

It does this by using the refrigerant circulating between the evaporator coil and condensing coil. The system drops the refrigerant pressure as it enters the evaporator coil, allowing it to easily absorb the heat. When it gets to the condensing unit, the compressor increases the pressure, allowing the refrigerant to vent the heat.

What Happens When Things Fail to Circulate?

Your air conditioner must be able to circulate both refrigerant and air to be able to run properly. If there is a restriction in the system anywhere, you will experience warm air, lower volume, or even a failure to turn on or to cycle situation.

If the air cannot cycle through your AC unit for some reason, the refrigerant cannot absorb heat. This leaves the refrigerant cooler than it should be, causing a freeze in the system.

If the air conditioner cannot regulate the refrigerant pressure properly, it also cannot absorb and release the heat. Either way, it prevents the pressure from dropping or rising, leading to a freeze somewhere in the system.

Dirty Air Filter

Your air filters are designed to keep airborne contaminants out of your system so they do not cause a restriction. However, if left unchecked, your filters may actually become the restriction. This will cause reduced airflow and warmer air coming from your vents, as it prevents the unit from functioning properly.

As mentioned earlier, this will also cause your system to freeze, which further exacerbates airflow restrictions. To avoid this, plan to check your filters regularly to ensure you are changing them when it is appropriate to do so.

Most experts recommend changing your filters about every three months, depending on filter type and air quality. If you check them monthly, you will be able to gauge more adequately when they need a change in the future. Further, you can extend the life of your filter by gently vacuuming the intake side to remove loose debris.

Refrigerant Leak

Refrigerant leaks cause several problems within your AC unit. First, they pose a health hazard if the leak is inside of your home, so they should not be ignored.

Second, they cause problems for the system regulating the pressure appropriately. When there is not enough refrigerant, the compressor still attempts to push the same amount into the condensing coils. This causes a drop in pressure in the refrigerant lines leading to the compressor, which then freeze up.

Circulating Fan Problem

Your circulating fan is responsible for moving the air through your system. It creates a vacuum on the intake side, drawing air into your unit. It then pushes the air through the evaporator coil and back out.

Circulating fans are one of the places where airborne contaminants tend to collect. This reduces the amount of air the unit can effectively draw and circulate.

Further, the fan motor will eventually fail, reducing the rotating speed as it does. This also prevents the system from circulating the appropriate amount of air. Both problems will lead to freezes at the evaporator coil.

Clogged Evaporator Coil

Your evaporator coil is where the refrigerant is coldest and where it absorbs the heat from the air in your house. It tends to collect airborne contaminants over time because of the constant flow of air through the coil.

These contaminants act in two ways preventing the system from absorbing heat properly. First, it causes airflow restrictions at the evaporator coil. Second, it creates a kind of film over the coil, which acts as an insulation, reducing heat transference.

What to Do Next

To prevent your air conditioner from freezing up, the best thing you can do is keep it properly maintained. Routine professional maintenance cleans the system, removing possible airflow restrictions. Your technician will also inspect your AC unit to ensure each component is operating optimally.

If your system does happen to freeze, shut it off to allow it to thaw again. Check your air filter to ensure it is not clogged, then call for a repair technician to troubleshoot your problem.

People around Beaumont have turned to the team at Reed Service Company for air conditioner repair and maintenance for over 45 years. We are also sought after for our expertise in heating installation, repair, and maintenance, along with indoor air quality solutions. Call to schedule an appointment with one of our expert technicians today. We are excited to be the company to serve your indoor climate comfort needs.