AC Frozen Inside: Why Does It Happen and What to Do About It?

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Last updated: 
April 29, 2024

Troubleshooting an AC Frozen Inside: Common Issues and Solutions

Common Issues with an AC Frozen Inside

An AC frozen inside can cause various problems that affect your home's comfort and energy efficiency. According to our research, some of the most common issues include:

Lack of Airflow

When an AC is frozen inside, it can lead to a lack of airflow, causing the unit to blow out warm air or struggle to cool your home effectively. This issue can result in premature wear on your unit and increased energy bills as the system works harder to perform its function.

A/C Stops Working

If you notice that your A/C unit freezes up or stops working altogether after running for some time, ice buildup could be the culprit. An AC frozen inside can cause ice to form on the unit's interior parts, blocking air to the system and potentially causing it to stop working.

Ice or Frost Buildup on the Unit's Parts

Low airflow to the A/C unit can decrease the temperature inside the system. When moisture in the air collects on the unit's components, it can create ice buildup on both the inner and outer parts of the A/C.

Caution: Never attempt to remove ice from your system by picking or scraping it off with a sharp object, as this could damage the parts and lead to costly repairs. Instead, turn off the system and allow it to thaw, or turn on the blower to help it thaw before troubleshooting.

Tools You'll Need for the Job

Nut Drivers and Sockets

When troubleshooting your system, you will need to access the system's inner parts. A set of nut drivers and sockets will be necessary to remove the panels and inspect the components.

Soft Brush

A soft brush, such as a toothbrush, can be used to gently remove debris from a dirty air filter or evaporator coils, which can hinder proper airflow to the system and cause it to freeze up.

Troubleshooting Steps for an AC Frozen Inside

According to our research, two main causes of an AC frozen inside are low refrigerant and restricted airflow to the evaporator coils. Follow these steps to troubleshoot the issue:

  1. Turn off the A/C: First, turn off the AC and set the fan setting to "on" to allow the system to thaw. Place dry towels around the unit to prevent water damage.
  2. Open the access panel to the evaporator: Remove the access panel to the evaporator and inspect the coils and cooling fins surrounding it. If there is debris, gently brush it off using a soft brush.
  3. Check the air filters: Check the filters in the cold air return inside your home or in the AC's plenum. If they are dirty, clean them gently with a soft plastic brush or replace them if they are beyond cleaning.
  4. Check for refrigerant leaks: Inspect in and around the system for visual signs of refrigerant leaks, which can sometimes cause a soft hissing sound. If you find any leaks, contact a professional HVAC technician to repair the leaks and recharge your system.
  5. Turn the A/C back on: Ensure the A/C supply registers in each room are open, as blocked registers can restrict airflow and cause the temperature inside the unit to decrease. Turn the A/C back on and allow it to run until it reaches the thermostat setting. If issues persist, contact a professional HVAC technician for repairs.

Other Issues that Can Cause an AC Frozen Inside

In addition to low refrigerant and restricted airflow, other factors can contribute to an AC frozen inside:

  • Wrong size ducts: Incorrect duct size or number can cause restricted airflow, leading to the system freezing up.
  • Wrong size condenser: The condenser size (BTUs) is determined by factors such as building size, insulation, and window type. An incorrectly sized condenser can cause the system to freeze up.
  • Bad blower motor: Consistent use and high heat can cause the blower motor on the A/C to burn out, potentially causing the unit to freeze up.

Caution Notes

Working with refrigerant, which can be a gas or a liquid, requires a licensed professional. When dealing with refrigerant leaks and repairs, always contact a licensed professional for assistance.

Final Thoughts

To prevent premature wear and tear on your A/C and keep your energy bills low, don't put off repairs when you encounter an AC frozen inside. Use this short guide to troubleshoot the issue and make the repairs you can handle yourself to save time and money. If the problem persists or you're unsure about any steps, contact a professional HVAC technician for help.

If you found this information helpful, consider sharing it with your friends on Facebook or other social media platforms. We'd also love to hear about your experience using these troubleshooting tips!

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