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My AC Line Is Frozen: What Happened?

Have you noticed that your air conditioner doesn’t seem to have the same cooling power it used to? It’s a good idea to give your AC system a once-over as soon as possible to try to identify the problem.

After removing the cover to your AC, do you notice that the lines or other internal components are frozen, or coated in ice? This is a sign that a bigger problem could be happening.

Why do AC Lines Freeze?

Typically, air conditioner lines freeze up when the unit’s evaporator coils get too cold.

The evaporator coil is one of the key parts of your AC system. The coil is full of refrigerant that is pumped through lines from the compressor. It then absorbs the heat from the air it pulls from the room.

The AC fan blows air over the coils, and this air is cooled as it passes over the refrigerant-filled coils, before blowing back out into the house. This is what happens when the system is working correctly, anyway.

However, if the line is restricted for some reason, the coil may not be able to absorb enough heat to balance with the coolant. This can cause the coil to get too cold, resulting in ice forming on the coils which can start to build up on the lines.

Some things that can cause this reaction are:

  • Refrigerant leaks
  • Bad blower motor or fan
  • Clogged or dirty air filters
  • Blocked or closed vents
  • Dirty evaporator coil

Refrigerant Leak

If a leak springs up where the refrigerant flows through your AC system, pressure levels will start to drop. Refrigerant will move through the lines slower, making its ability to cool lessen. There will also be a reduced amount of refrigerant available due to loss from the leak.

If the balance between warm air over the coils and the amount of coolant inside is out of balance, ice can form. This can hinder the air-cooling process.

If your air conditioner is making pulsating noises or gurgling, or if only warm air is coming out of the AC vents, you may have a refrigerant leak. An air conditioner with low pressure due to a leak will have to work harder and stay on longer. This can result in more wear and tear on the unit and higher electricity bills.

Bad Blower Motor or Fan

If the blower motor isn’t working or has died, the fan can’t draw in enough air to balance the coolant in the lines. When this happens, AC lines form frost or ice on their exterior. They also stop working efficiently.

If your air conditioner fan is making a humming noise or seems to be spinning slower, you may have a bad blower motor.

Likewise, a busted or damaged fan won’t be able to send enough air over the coils to maintain a balance. This leads to icy build-up and little cooling.

The AC’s fan not only pulls air into the system but blows cooled air into the room and warm air out through the outtake vent. Since the fan is the engine that keeps everything moving, if it stops functioning, the whole air conditioner stops working.

Clogged or Dirty Air Filters

A clogged or dirty air filter affects your air conditioner in the same way as a bad fan. It minimizes the volume and speed of the air circulating through the system.

Professionals recommend that air filters are replaced every few months. The recommendation may be more often if you live in an area with excess air pollution or smog. Changing the air filter in your air conditioner may solve your ice problem, but it may only be masking a larger issue.

The best thing to do if you have a concern about your AC system is to contact a professional for AC repair.

Blocked or Closed Supply Vents

Oftentimes, new air conditioner owners assume that blocking or shutting vents in certain rooms will increase the cooling efficiency in the remaining rooms. This is not the case.

If your air conditioner is made to cover a certain area of square footage or is set to a specific output, closing or blocking vents increases the pressure and adds stress to the entire system.

This increased load and backed-up pressure can slow the airflow, allowing the coils and lines to get too cold and form ice.

Dirty Evaporator Coil

Much like a clogged air filter, a dirty evaporator coil can affect proper airflow. Dirt and grime on the exterior of the coil can act as an insulator, lessening the effect between the coolant and the air it’s cooling.

How To Unfreeze AC Coils

Based on these possible causes, there are several things you can do to address the problem of ice on your air conditioner coils and lines.

Switch Your Air Conditioner from Cool to Fan Mode

Switching out of cooling mode turns off the air conditioner’s compressor and stops the flow of coolant. This leaves only the fan running to move air into and out of the system.

Simply, this is like defrosting your freezer.

By turning off the mechanism that cools the incoming air, the whole system warms up and anything that’s frozen will thaw out. Typically, you would want to leave the system in this mode for three to four hours to complete the thawing process.

Often this can return the system to the proper balance if it’s gotten a little out of calibration over time.

If you notice ice reforming when you turn the system back to cooling mode, then you could have a more serious issue. Try the remaining steps or turn the system off and contact a professional immediately.

Check and/or Replace the Air Filter

First, visually inspect the air filter. If it appears dirty or worn, it’s likely reducing the airflow to the air conditioner. Replace it and see if that resolves your ice problem.

Be sure to check the AC unit’s evaporator coil for any physical damage like bent coil fins, loose or damaged connections, broken pipes, or damaged fittings. Issues of physical damage could lead to much bigger and more expensive problems down the road. Only a licensed, professional technician should replace these.

If none of these solutions work and ice continues to form on the coils or lines of your air conditioning system, contact a professional to determine and repair the root cause.

Why Choose a Professional

Ice forming inside an air conditioner is a common problem. It can occur when something is stopping the proper airflow, or the refrigerant is compromised.

This allows the coil or lines to drop below a temperature that can freeze the condensation. Other issues, like bad or damaged wiring, dirty coils or a broken AC fan can lead to this as well.

Ice buildup places stress on your AC system, resulting in more frequent repairs and high energy costs.

Freezing air conditioner lines are a serious issue and one that you shouldn’t ignore or put off dealing with. The longer that frozen lines remain an issue, the greater the likelihood of more permanent damage or system failure.

Contacting an air conditioner professional is the quickest and most cost-effective solution. A professional is qualified to determine any regular maintenance or specific repair problems with your system. They have the experience and the tools necessary to deal with your AC issues and provide long-term solutions. You can even rely on them for honest advice on when it might be best to replace your AC unit.

Hiring an experienced professional means getting the best value on your investment and helps avoid more frustration in the future.

ABC Can Get Your AC Unit Running Smoothly Again

It can be tough to diagnose your AC unit on your own. Instead of trying to fix the problem yourself, contact ABC Home & Commercial Services. Our licensed specialists can diagnose your AC problem and then make all needed repairs. This way, you and your family members won’t have to worry about your AC malfunctioning or not working at all.

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