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What Causes an Air Conditioner to Freeze Up: Diagnosis and What You Should Do

Most property owners want their AC system blowing cold air, especially in the summer months. The idea that an air conditioner can actually stop working if it freezes up may feel odd, but it can happen. What causes an air conditioner to freeze up, and how can you avoid this situation?

Air conditioners often freeze up as a reaction to other problems, like refrigerant leaks or electrical breakdowns. Learn more about air conditioning repairs and how to handle a frozen air conditioner with our team at Rock Valley HVAC, Inc. You can reach us at (608) 247-4949 to speak with an HVAC professional.

Air Conditioner Functions and Freezing Up

You count on your AC unit to make cold air, so shouldn’t it be a good thing if the unit gets even colder? While this seems like a logical assumption, certain parts of your air conditioner require warm air to function.

Your AC unit contains both evaporator and condenser coils, which carry refrigerant. Refrigerant is a chemical that becomes extremely cold. Your system must blow warm air over the coils to transport the refrigerant, or they become so chilled that they freeze and stop working.

You may also end up with a unit freezing due to a breakdown. We often see more frozen AC units when the weather gets humid. Excess moisture in the air makes it easier for ice to form on the pipes in your AC unit, increasing the problem.

Improper Air Flow Can Cause AC Units to Freeze

what causes an air conditioner to freeze up

What causes an air conditioner to freeze up? Improper ventilation represents the primary reason for AC units to freeze inside. Your system requires proper airflow, including warm air, to keep the refrigerant moving freely through the coils.

Your system may experience a lack of airflow for several common reasons, such as those listed below.

Duct Collapse or Blockage

AC units use ducts to transport indoor air through your home or business. Sometimes these ducts collapse or become clogged with substances like:

  • Dirt
  • Dust
  • Pet hair

A blockage or collapse prevents air from returning to your outdoor unit to blow over the coils, which can cause the entire system to freeze up. You may notice the same problem if the air filter in your HVAC system gets clogged.

The Blower Motor Fails

An AC unit’s blower motor directly propels warm air across the coils inside. These motors may wear out and break down over time. You may notice a rattling sound as your blower fan motor begins to give out, warning you of a potential problem.

How To Handle Improper Air Flow

You may handle improper airflow problems on your own in some cases. Before you start, please turn off your air conditioner to allow it to thaw out for one to three hours. During this time, you can check the filter and change it if it appears clogged. Taking these steps may resolve your issue.

More severe blockages or issues with your blower motor may require professional help. You can reach out to an HVAC team to get assistance with these repairs.

Low Refrigerant and Frozen AC Units

The refrigerant in your AC unit is very cold. Some property owners think unusually low amounts of refrigerant should cause your AC unit to warm up instead of freezing. The opposite effect usually occurs because low refrigerant levels cause your system to cycle through the remaining refrigerant too quickly, leading to a freeze.

You may notice this issue if you spot ice forming directly on the copper pipes around your coils. Low levels of refrigerant may result from a leak. These leaks can develop due to:

  • Normal wear and tear
  • Corrosion from the inside of the pipes
  • Vibrations or exterior damage

Rock Valley HVAC, Inc. can help you handle a leaking refrigerant line and resolve your freeze-up issues.

How To Handle Low Refrigerant

Refrigerant is a toxic chemical. Exposure to refrigerants can lead to several medical issues if mishandled. For this reason, the professionals usually recommend that you reach out to an AC repair specialist for help if you suspect your AC unit froze over due to a refrigerant leak.

Excess Dust and Frozen AC Units

Finally, you may notice your AC unit experiencing issues with freezing over if excess dust enters the unit itself. This dust can get into your unit if you have a problem with your filter. The dust can then stick to moisture on the outside of your evaporator or condenser coils, forming an insulating barrier.

Once the coils become insulated, they often hold the cold in, resulting in ice spreading over the copper tubing and coils.

How To Handle Dust on Your Coils

There are some immediate steps you can take to handle a freeze-up caused by dust in your AC unit. First, make sure you turn the unit off to allow the ice to melt and give your unit time to recover. While the unit remains off, you can gently spray the coils with a hose to remove the excess dust.

You can turn your AC unit back on after completing the cleaning process to see if the unit functions properly. You may also contact the professionals to handle a frozen AC system. Regular maintenance can stop your AC system from freezing up in some situations.

Our crews can perform yearly maintenance to ensure your refrigerant levels are normal and clean your coils. These steps can keep your AC system functioning properly for many years to come.

Our Air Conditioning Repair Services

You can contact our team at Rock Valley HVAC, Inc. for air conditioning repair in Milton. We can answer all of your HVAC-related questions, including what causes an air conditioner to freeze up. We can also schedule you for regular maintenance to keep your AC unit in good condition.

You can easily reach out to us if your AC unit freezes over and you cannot fix the issue on your own. Reach our crew by calling (608) 247-4949.

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