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Why Does My Air Conditioner Keep Freezing Up?

Our HVAC contractor Toronto often get asked, “how do I keep my air conditioner from freezing up?” It helps to know why your AC is freezing up in the first place. Usually, your AC freezing up results from a problem with the heat transfer process within your unit. This can be caused by several different factors, including a dirty air filter, low refrigerant levels, or a problem with the airflow of your AC unit.

Split central air conditioners, which are the most common type of central air conditioners in Canada, function by pushing warm air out of your home and into the outdoors. In order to do this, your AC unit relies on a fan to blow air over a set of coils. These coils are filled with a refrigerant, which helps to cool the air as it passes over them. This process involves a transfer of heat.

When this heat transfer fails to take place efficiently, it can cause your air conditioner coils to freeze. This usually happens as a result of one of four things:

A Dirty Evaporator Coil

When dust and dirt build up on your evaporator coil, it can restrict the airflow around the coil and prevent heat from being transferred effectively. This will cause your AC unit to work harder to cool your home, which can lead to the coils freezing up.

Low Refrigerant Levels Due to a Leak

Another common cause of AC units freezing up is low refrigerant levels. This can be caused by a refrigerant leak somewhere in your AC unit. When the refrigerant level gets too low, it can prevent the coils from cooling properly, which can cause them to freeze up.

Poor Airflow

Another reason your AC unit is freezing up is poor airflow. This may occur as a result of dirty air filters, blocked supply registers, or a problem with the fan. If there is not enough airflow around the coils, they will not be cooled properly and may freeze up.

Low Outside Temperature (16 degrees Celsius)

To be able to move heat outdoors, central air conditioners rely on the temperature difference between the inside and outside of your home. If it is very cold outside, this temperature difference may not be enough to allow your AC unit to operate efficiently. As a result, your coils may freeze up.

If you think any of the issues discussed above might be causing your AC unit to freeze up, you should have a professional check your unit as soon as possible. Are you still wondering “how do I stop my air conditioner from freezing over?” There are several things that you can do to prevent your AC unit from freezing up. Read on to find out.

How Do You Know If Your AC is Frozen?

Now that you have an answer to “why does my AC keep freezing up?” the next thing is to discuss all the different signs indicating you have a frozen AC unit. Like most AC problems, it helps to catch the issue early. When your air conditioner is frozen, you may feel like all hope is lost. But don’t worry! The problem is usually much easier to fix than you might think. There are a few telltale signs that your AC unit is frozen:

The first sign is usually that there is ice on the refrigerant line pipe. You may also see ice on your evaporator coil. If you see ice on the coils, your AC unit is likely frozen. You can tell if the evaporator coil is frozen by looking at the AC line between your home and your outdoor unit.

Another sign that your AC unit might be frozen is if it is not blowing out cold air. This is usually due to the fact that the coils are not able to transfer heat properly when they are frozen. Condensation on the indoor unit also indicates that your AC unit is frozen. If you notice any of these signs, it is important to take action immediately to prevent further damage to your AC unit.

Why Does Your AC Keep Freezing Up?

Low Outside Temperature

As mentioned earlier, one reason why your AC unit might keep freezing up is because of a low outside temperature. If the temperature outside is lower than 16 degrees Celsius, it can cause your AC unit to freeze up. So, what can you do about it? How do I keep my air conditioner from freezing up? While low temperatures in the summer are usually not a problem in Ontario, it can be a problem if you live in another province where the temperature sometimes dips below 16 degrees Celsius. If this is the case, you can try to prevent your air conditioner freezing up in summer by turning off the unit when the temperature outside is low.

Improper AC Unit Installation

Why is my brand new ac unit freezing up? If your brand new AC unit is freezing up, it is likely because it was not installed properly. Improper installation is one of the most common reasons an AC unit keeps freezing up whenever you need it the most. Failing to insulate the evaporator coils is one installation problem we see very often. These coils, located in your ductwork, can cause your AC unit to freeze if they are not properly insulated.

Another installation problem that can cause your AC unit to keep freezing up is when your unit is not level. Always get a professional team like AirMakers to install your AC unit to avoid these problems.

AC Parts Are Worn Out

Your air conditioner has moving parts that can wear out over time and cause your AC unit to freeze up. One of these parts is the fan motor. Although it is made to last a long time, the fan motor can eventually burn out. When the fan motor starts to fail, it can cause the coils to freeze because of a lack of airflow. The compressor is another part that can fail and cause your AC unit to keep freezing up. When the compressor fails, it can no longer pump refrigerant through the system, which can cause the coils to freeze. While replacing the worn-out parts in your AC unit can help, sometimes the only solution is to replace your air conditioner.

Clogged Filter

The first place you should inspect is the air filter. When clogged, air filters can obstruct the flow of air to the system leading to frost on the coil. Needless to say, if the AC doesn’t get enough air, it will not work properly. In most cases, restricted airflow is caused by a dirty air filter. You can find the filter in the air handler of the furnace. Turn everything off, then remove the filter. It should be cleaned at least once every month and replaced within three months. To clean the filter, you should use warm water and gentle soap. Ensure it’s 100% dry before installing it back into the air handler.

Air Conditioner is Too Cold

While this might seem like an obvious point, there is more to it than that. The air conditioner may get too cold when the thermostat is turned extremely low. To prevent the AC unit from freezing up, you should set the thermostat at 25 degrees Celsius. The AC may also be too cold if the weather outside is chilly. This is common at night during spring and fall. If there is expected to be an overnight low of below 16 degrees Celsius, you should turn off the AC before going to bed.

Blocked Condensate Drain

The AC works by converting a refrigerant from liquid to gas form. The evaporation process releases moisture which is removed by the condensate drain line. When the drain line is not cleaned regularly, algae and other forms of vegetation will grow and block it. The blockage may cause the coil to freeze up. The solution to this issue is to power off the air conditioning and flush the drain line using white vinegar or warm soapy water.

Dirty Evaporator Coil

When the evaporator coil is dirty, the coil will not be able to absorb heat. As a result, the refrigerant will remain at a frigid temperature. This causes the coils to ice up. To solve this problem, you need to defrost the coil and clean it thoroughly. You can also bring in a professional to help with maintenance.

Low Refrigerant

Refrigerant leaks are a bad sign. This is because you need a consistent level of refrigerant for the AC to work properly. When there is a leak, the amount of refrigerant being compressed and expanded will be lower. This creates a cooler temperature in the AC. In addition to cooling your home, the AC serves as a dehumidifier. The moisture being passed over the coil creates condensation. If the coil has temperatures that fall below freezing, the condensation will freeze up. You must get refrigerant leaks fixed right away.

If Your Air Conditioner is Freezing up, We Can Help

We hope we have been able to answer your question, “how do I keep my air conditioner from freezing up?” If you are still having problems with your AC unit, our team of experts at Air Makers are here to help. We offer a variety of professional HVAC services, including AC repair, AC replacement, and AC installation. We also offer regular maintenance checks to keep your unit running smoothly all year long. Contact us today at [phone] to schedule a service call or tune-up! Our team of friendly HVAC technicians and support staff is always eager to help.

How To Keep Your AC From Freezing Up

Regular AC Maintenance

An annual professional tune-up can extend the lifespan of your unit while preventing many common issues, such as a frozen AC unit. During maintenance, a professional will:

  • Perform a visual examination of the unit
  • Clean the evaporator coils and other parts of the unit
  • Inspect all electrical components for damage or loose connections
  • Test the refrigerant levels and top off if needed
  • Examine the condensate drain to ensure it is clear
  • Lubricate all moving parts including the fan motor and blades
  • Inspect coolant levels and pressure so that your system will run at peak efficiency
  • Calibrate your unit’s thermostat to ensure your home is comfortable
  • Inspect the condenser and clean it if necessary
  • Examine the compressor amps during startup
  • Check the unit again and carry out other necessary checks including safety and efficiency tests

To keep your home safe, it is best to leave air conditioner maintenance to a professional. Your AC contains coolant chemicals and electrical components that require special training to handle safely. Our team of experts at Air Makers is here to help you with all your air conditioner needs. Schedule a tune-up today and let us help you keep your home cool and comfortable all summer long!

Check If Your Air Filters Need to Be Changed

As we mentioned earlier, one of the main reasons why an AC unit can keep freezing up is because of a dirty air filter. While your HVAC system is busy all summer keeping you and your household comfortable, your air filter is also at work catching dirt, dust, pollen, and other allergens that can cause respiratory problems.

That’s why it’s important to check and clean your air filter regularly, especially during the summer months when your AC is working overtime. A good rule of thumb is to check your air filter at least once a month.

When your air filter is clogged with dirt and dust, it can restrict airflow and cause the coils to freeze. We recommend changing your air filter every 1-3 months, depending on the type of air filter you have. If you have pets or children in your home, you might need to change your filter more often.

Other reasons why you may have to change your air filters more frequently include:

  • If you live in an area with a lot of dust or pollen
  • If someone in your home has allergies or asthma
  • If you have a smoker in your home

Make Sure to Clean Evaporator Coils

To keep your system running properly, it is important to clean the coils on a regular basis. If you can’t do it yourself, hire a professional like AirMakers to do it for you.​​ It’s actually one of the most important things you can do to prevent your AC unit from freezing up. Over time, dust and dirt can build up on the coils and restrict airflow which can cause the coils to freeze. This will make it difficult for your AC unit to cool your home or it may shut down altogether.

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