Serving Greenwood, Fishers, Carmel & Surrounding Areas

May 24, 2021

What Causes Your Air Conditioner to Freeze Up?

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Your air conditioner is a complex system with many possible problems. One common issue that people run into is their system freezing. What causes your air conditioner to freeze up, what should you do when it does, and how can you prevent it?

Knowing When You Have a Problem with Your Air Conditioner

The first step is to know when you have a problem with your air conditioner. There are several telltale signs of an issue, even before you notice something more obvious like ice forming on your unit somewhere.

First, you may notice your air conditioner is not cooling as effectively as it should. You may discover warm air coming from your vents or just not enough air coming through as your system runs.

You may also notice your condensing unit, which sits outside, is either not running or making a chattering sound. These are signs there is a problem that needs your quick attention to prevent damage to your unit’s components.

Then, there is the ice that you may see on your system. You will usually notice this near the refrigerant lines as they come into the condensing unit. If you look inside the unit, you may see ice around the condensing coil or on the compressor.

Inside, you may notice an unusual amount of water in the drip pan under your air conditioner. You will typically see this after the system shuts down as the ice melts off of the evaporator coil.

All of these signs point to a problem with your air conditioner and may indicate that your system is freezing. Before looking at what causes those freezes to occur, let us look at how your unit works and what causes freezing in general.

Air Conditioning Basics

Before jumping into the specific causes of freezes in your air conditioner, it may be good to understand how your system works. Your air conditioner operates by circulating air and circulating refrigerant. If there is a problem with either of these, it causes your system to malfunction.

The way that your air conditioner cools your home is by absorbing the heat from the air and transferring it outside. It can accomplish this because of how the unit handles the refrigerant.

When the pressure of the refrigerant drops, it becomes extremely cold, allowing it to absorb heat. Then, when the pressure increases, it becomes very warm, allowing it to transfer the heat outside.

If something happens and the system cannot properly adjust the pressure of the refrigerant, your air conditioner cannot work. Likewise, if the system cannot circulate the warm air in to transfer the heat out, it will not work. Now, let us look at what happens that can cause the unit to freeze up.

Clogged Air Filters

You have probably had the pleasure of changing your air filters at some point or another. However, you may not realize how important your filter is to your system. It helps keep contaminants out of your air conditioner, minimizing the risk of an airflow restriction.

Because the filter collects dirt and particles, however, it will get clogged at some point and need to be changed. If your air filter gets clogged, it prevents the correct volume of air from flowing through your system.

Without the right amount of air flowing over the evaporator coils, the refrigerant does not absorb heat and warm up. This leads the chilled low-pressure refrigerant to freeze the evaporator coils.

A frozen evaporator coil further prevents air from flowing through the coil, exasperating the problem. Keeping your air filters clean will allow the right amount of air to flow through the unit.

Dirty Evaporator Coils

Your evaporator coil is inside, usually as part of your air handler or furnace unit. As your air conditioner runs, air flows through the coil, where the refrigerant absorbs the heat from the air.

No matter how good your air filters are, some number of contaminants will make their way into your system. These settle on several AC components, including on the evaporator coil. As the coil collects these contaminants, they will absorb the moisture that the evaporator coil condenses from the air.

The mixture of this moisture with these contaminants creates a thick coating on the coil surface. This coating insulates the coils, preventing the heat from efficiently transferring to the refrigerant. Like a clogged air filter, dirty coils can cause the coils to then freeze.

Circulating Fan Problems

Your circulating fan can also pose a problem that will lead to your system freezing. As the circulating fan runs, it collects airborne contaminants. As it does, it reduces its effectiveness in moving air through your air conditioner.

The circulating fan draws in air through the intake vent and air filters. It then pushes that air through the evaporator coil and back out into your house. In order to draw the air in through the air filter, it must create a certain amount of vacuum.

In addition to the fan collecting contaminants, the motor itself can cause problems that prevent proper airflow. Motors eventually wear out, especially if the bearings are not lubricated periodically. When this happens, the motor will start spinning more slowly, preventing the fan from creating the right air draw.

Refrigerant Leaks

Your system must have a certain amount of refrigerant in it to make it run properly. When it has too much or too little, it cannot effectively absorb heat and transfer it outside.

Air conditioners often develop small refrigerant leaks, especially without proper system maintenance. These leaks reduce the amount of refrigerant in the unit, preventing the compressor from reaching the correct pressure and temperature.

This lack of proper pressure can create frozen blocks in several areas of your air conditioner. The lack of pressure can cause the system to freeze at the evaporator coil and leading up to it.

However, if the leak is at the compressor or in the condensing coil, it can cause the refrigerant lines, compressor, or condensing coil to freeze. No matter what causes the freeze in your unit, it prevents it from cooling and causes additional damage.

Dealing With a Frozen Air Conditioner

Dealing with a freeze can be a bit tricky and take some investigating. If you suspect that your system has a freeze somewhere, shut it down right away. Once it is off, check your air filters to make sure they are clear. Then, call a technician to come and find the root cause of your problem.

Ultimately, the best way to deal with a freeze is to prevent it from happening in the first place. The best prevention is with routine maintenance. During a maintenance visit, a technician will check your refrigerant level and ensure that there are no leaks. They will also inspect and clean your condensing and evaporator coils as well as your circulating fan. The inspection is designed to prevent freezes and uncover minor problems that may lead to larger issues at some point during the season.

Complete Comfort has been a trusted partner around Greenwood for air conditioning maintenance and repair since 2003. People also turn to us for heating and plumbing installation, maintenance, and repair. Call to schedule your air conditioner maintenance with our team today.

When it comes to your home or business cooling system, if you find yourself in need of AC repair in Greenwood, IN, you need to know you have a trusted professional on hand to get you back to comfort levels in no time. That’s where we come in. We’ve been serving Central Indiana since 2003, and offer the highest quality of air conditioner repair and services in the area. Our technicians will treat you like family, and work with you to find the best possible solutions for your repair and comfort needs.