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frozen ac line

Frozen AC Line: Why It Happens & What To Do About It

A frozen AC line can be a rather peculiar sight in a place like Phoenix, Arizona where nothing ever freezes. In this post, we’ll discuss what makes an air conditioner line frozen – and what you can do about it.

Causes Of A Frozen AC Line

Ice shards used to represent the concept of a frozen AC line.

These are the two most common culprits behind a frozen AC line.

Dirty Air Filters

Did you know that you should be cleaning or replacing your air filters on a monthly basis? Failing to do this can result in airflow issues that, in turn, cause your evaporator coils and lines to freeze over. You’ll notice a buildup of ice on both components, although the buildup on your pipes will, of course, be more evident unless you open your air condition up to reveal the coils.

What To Do About It

Give your air filter a good cleaning if it’s reusable. If not, replace the filter outright. Next, switch your air conditioner’s fan setting on and leave it there for 2-3 hours. This will draw warm air in, helping to thaw your evaporator coil. You can also check out this article for some tips on cleaning the coils themselves if you’d like to speed the process up. Before you switch the unit back to its normal state, make sure the supply vents are completely unobstructed and free of dust or other debris.

If you keep having this issue even after replacing your filters regularly, contact a local HVAC repair company and have them inspect your evaporator coil, ductwork, and any other components that may be at fault. If you live in the Phoenix, Arizona area, give American Home Water and Air a call.

Low Refrigerant Levels/Leakage

Reduced refrigerant levels can cause a drop in your air conditioner’s pressure, which in turn reduces the remaining coolant’s temperature. If this dips low enough, you’ll end up with frozen pipes.

What To Do About It

Contrary to what air conditioner “recharge” companies often tell their clients about refrigerant, it should never need to be simply refilled. You see, refrigerant runs in what experts refer to as a “closed loop.” Refrigerant really shouldn’t be leaving that loop. If it is, you’ve got a leak.

Paying someone to come and pump more refrigerant into your system (aka “recharge” it) isn’t the solution. Doing that will simply kick the can down the road. Besides, refrigerant leaks can be harmful to the environment and people in your home.

Rather, you need to take care of the leak with the help of a technician. Check out this article for some more information about dealing with air conditioners that are leaking refrigerant. Before you contact a technician, switch your thermostat to the off position. Then, switch the fan setting on and let it run for 2-3 hours so the unit can thaw.

Improper Temperature Setting

Improper temperature settings can also cause a drop in your air conditioner’s pressure. What many people don’t realize is that air conditioners are actually designed to run when temperatures have fallen above roughly 60 degrees Fahrenheit. If you run the unit when it’s cold outside, you’ll run into many issues, including frozen components.

What To Do About It

Make sure your air conditioner is switched off during the colder months. While you may be tempted to use it for defrosting your windows or something of that sort, the downsides far outweigh any benefits.

Faulty Or Dirty Blower Fan

Your air conditioner’s blower fan is responsible for circulating air around the unit. If the fan’s blades have gotten clogged up with dust and debris, they’ll turn slower. As a result, your air conditioner will end up with reduced airflow. As you probably know by this point, that’s a recipe for frozen components.

What To Do About It

Alternatively, the blower fan can also slow down if it’s faulty. With a well-built air conditioner, this is usually the result of age. You can rule this out by opening up your air conditioner as if you were going to do a deep internal clean. Check out this post for instructions on doing that with a window air conditioner. If the fan is clean, contact a technician. You’ll likely need to have them replace the fan motor. If the fan is dirty, wipe the debris away from it. If the problem persists, contact a technician.

Act Fast When You Have A Frozen AC Line

A frozen AC line isn’t something to ignore or put off dealing with until later. Leaving the unit running while its components are frozen can stress the compressor. The longer you leave the system like this, the more likely you are to permanently damage it. Replacing a ruined compressor rather than the whole unit is often economically infeasible, meaning this can turn into a very costly repair.

Even before something this catastrophic happens, you’ll notice that your air conditioner runs quite inefficiently, leading to higher electricity bills. This adds up quickly, making the cost of having a technician service your unit seem like chump change in comparison. To learn more about some common AC issues check out our other articles such as “AC Light Blinking (Causes & How to Fix It Fast!)”

What Does A Technician Do When Rectifying An AC Unit Line That’s Frozen?

A good technician will replace your filters if you haven’t done so already. If that’s not the issue, they’ll inspect your air conditioner’s various components to narrow it down. A good air conditioner service looks at many different factors in order to identify the underlying issue. At American Home Water and Air, for example, we have an unrivaled 40-point checklist we run through as part of our HVAC service.

If you don’t live near us, check out this article for some tips on how you should go about choosing the right HVAC company for your needs. If you have other issues with your HVAC or AC units feel free to check out our other articles on issues like air conditioner still running when turned off.

Frequently Asked Questions

What causes AC lines to freeze up?

There are a few potential causes of a frozen AC line. The first is reduced airflow caused by a dirty filter or faulty fan. The culprit may also be reduced air pressure caused by a leak or improper temperature settings.

How do you unfreeze an air conditioner?

You can switch the unit to “fan” mode and leave it there for 2-3 hours. This isn’t a permanent solution, however; it just thaws whatever ice was there at the time.

How long does it take to thaw a frozen air conditioner?

You should be able to achieve this within 2-3 hours using the air conditioner’s fan setting.

How long should I leave my AC off while frozen?

If you’re using the fan mode setting, it should only take 2-3 hours. However, you shouldn’t return the unit to its default setting until you’ve addressed whatever caused it to freeze in the first place.

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