Have you noticed that your coil has frozen or there’s been a lot of water around the floor of your indoor unit? While your air conditioner should get cold, it should not freeze up if it’s working properly. Discover why your air conditioner freezes up and what you should do when it does.

Why Does Your Air Conditioner Freeze Up?

Let’s start with why your air conditioner would freeze up in the first place. To understand this, you have to understand a bit about how your air conditioner works.

On a simple level, your air conditioner absorbs heat from the air moving through the system. The refrigerant performs this task at the evaporator coil and drops in pressure. Once it absorbs the heat, it has to vent it, which it does when it’s compressed into a high pressure at the condensing coil.

What actually freezes is condensation that forms, usually on the evaporator coil. Just as a cold glass of liquid has water forming on its surface on a hot day, your air conditioner causes the same thing to happen. It’s called condensate This is actually a secondary benefit of your air conditioner. It removes some humidity from the air. Knowing this helps you understand why your system might freeze. There are really three primary causes that lead to a frozen AC.

The most common reason, and also the easiest to solve, is an airflow restriction. When air can’t flow through your system effectively, the system cannot absorb enough heat, which leaves the refrigerant too cold. Your refrigerant keeps getting colder, eventually becoming cold enough to freeze.

The second reason is that your system may not have enough refrigerant in it, which could be due to a leak somewhere. This leads to the system growing too cold, and it could cause a freeze in the refrigerant lines or elsewhere. Seeing where the system is frozen may give you a good indication of where the leak is.

Finally, you may have some mechanical issue that’s causing the freeze. The most common is a problem with the compressor failing to raise the referent’s pressure. Less commonly, you may have an expansion valve problem. Additionally, it could be an issue with the circulating fan failing to distribute the right amount of air through the system.

You may not know the cause of the freeze when you first notice it, so your goal is to try to find it. The following steps will both help you troubleshoot the issue and help protect your system from significant damage.

Signs Your Air Conditioner Is Frozen

The obvious sign of a frozen air conditioner is visible ice on exposed refrigerant lines at the compressor or on the condensing coils. You likely won’t see the inside evaporator coils, but you may notice water around the inside unit between cycles. Other signs of your system freezing include the following:

  • Short cycling
  • Reduced airflow
  • Warm air coming from your vents
  • A hissing sound coming from somewhere in the system

Turn It Off

If you suspect you have a frozen system, you’ll want to turn it off immediately. Keeping your system running once it’s frozen may burn out your compressor, which typically means you’ll have to replace the entire unit.

There are a couple of ways to turn your AC off. The easiest is to turn it off at the thermostat. Simply switch it from “Cool” to “Off.” There’s no need to turn on the heat.

The other way to make sure it’s off is to turn it off at the circuit breaker. If you’re going to do any deep investigation, you’ll want to kill the power to the unit by terminating power at the breaker.

You’ll want to leave it off long enough for the frozen section to thaw. This usually means you’ll leave it off for between three and four hours. Trying to restart it before it thaws completely will only lead to the system freezing again and risk further damage. Do not attempt to use a hair dryer or space heater to thaw your system, which could risk a dangerous electrical shock or electrical fire.

Check Your Air Filter

While you’re waiting for your system to thaw, check for the most common airflow restriction, which is a dirty air filter. When you check the filter, you can visibly see if there’s a lot of dirt or dust that’s collected in the filtering media.

To be sure it’s not the problem, consider changing the filter if it looks dirty. If it’s not overly dirty, gently vacuum the filter to give it a little extra boost in its performance.

Dry Out Your Coils

Next, you’ll want to dry out the system, which usually means one or both of the coils. Just like starting the system before it’s had a chance to thaw, starting it with wet coils increases the risk of another freeze.

Chances are that when you experience a freeze, the weather outside is hot, and possibly sunny. This will naturally dry out your outdoor condensing coil.

However, your indoor evaporator coil may need some help drying out. The best way to do that is to let the circulating fan continue to run. As long as you haven’t turned your unit off at the circuit breaker, you’ll just need to adjust the thermostat. Change the fan setting to “On,” which keeps the fan running constantly, even without the AC compressor operating. This will continue circulating warm air over the evaporator coils, helping them both thaw and dry out.

Have Your Refrigerant Checked

If your filter isn’t dirty, you should have your refrigerant level checked. This isn’t something you should attempt on your own because it requires specialized equipment. A technician will connect gauges to both the high and low-pressure lines to test the refrigerant’s pressure. Not only will this give them an indication of a refrigerant leak, but it can also tell them if your compressor is failing.

For instance, low pressure before the compressor indicates a refrigerant problem. However, proper pressure before the compressor but low pressure afterward indicates a problem with the compressor raising the pressure.

Get Your Evaporator Coil Cleaned

Your evaporator coil is one of three primary places that collects airborne contaminants like dust and pollen. Yes, your filter does a good job catching most of these particles. However, tiny particles will flow through your filter and settle on the coil and your circulating fan.

Ideally, you should have the evaporator coil cleaned annually. This not only ensures that there aren’t any airflow restrictions as the system runs, but it also prevents corrosion that contaminants can cause.

Easiest Way to Prevent Freezes

The easiest way to prevent any freeze in your system is through annual professional maintenance. During a maintenance visit, your technician checks the refrigerant level, cleans the evaporator coil and circulating fan, and tests the compressor. The only thing left for you is to change the air filter regularly to prevent airflow restrictions at the beginning of the process.

When needing dependable AC or heating service, people in the Miami and Ft. Lauderdale areas turn to our team at Quality Air Of America in Miramar. We’ve served over 50,000 customers. Our expert technicians provide air conditioning and heating maintenance, installation, and repair along with indoor air quality solutions. Call today to schedule your air conditioning maintenance appointment to keep your equipment functioning in top condition.

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