What to Do When Your AC Freezes Up


When your air conditioning (AC) unit freezes up, it indicates a problem that needs to be addressed promptly to prevent further damage to your system. Here’s what you should do if your AC freezes up:

1. Turn Off the AC

As soon as you notice ice buildup on the AC unit or notice that it’s not cooling properly:

  • Turn Off the Thermostat: Set your thermostat to the “off” position to stop the cooling cycle.
  • Turn Off the Power: If possible, turn off the AC unit’s power at the breaker box to prevent further operation.

2. Allow the Ice to Thaw

Let the AC unit thaw completely before attempting any further action:

  • Fan Only Mode: You can set your thermostat to “fan only” mode to help thaw the ice faster. This mode circulates air through the system without cooling.
  • Wait: Depending on the severity of the ice buildup, it may take several hours for the ice to melt completely. Ensure the area around the ac repair denver is clear to prevent water damage.

3. Check for Common Causes

Once the ice has melted, investigate common causes of AC freezing:

  • Airflow Restrictions: Check air filters and replace them if dirty. Dirty filters restrict airflow, leading to ice buildup on the evaporator coils.
  • Blocked Vents: Ensure all vents and registers are open and unblocked to allow proper airflow.
  • Low Refrigerant Levels: Low refrigerant levels can cause the evaporator coils to freeze. This indicates a possible leak that needs professional attention.

4. Clean or Replace Filters

Dirty or clogged filters are a common cause of AC freezing:

  • Inspect Filters: Check the condition of your air filters. If they are dirty or clogged, replace them with new ones.
  • Regular Maintenance: Establish a regular schedule for checking and replacing filters every 1-3 months, depending on usage and filter type.

5. Inspect and Clean Coils

Dirty evaporator coils can also contribute to freezing:

  • Visual Inspection: Inspect the evaporator coils for dirt, debris, or ice buildup. Clean them gently with a soft brush or vacuum to remove dirt and improve airflow.
  • Professional Cleaning: For thorough cleaning, consider scheduling professional maintenance to clean both the evaporator and condenser coils annually.

6. Check Refrigerant Levels

Low refrigerant levels or leaks can cause the AC to freeze:

  • Professional Inspection: If you suspect low refrigerant levels or a leak, contact a licensed HVAC technician for inspection and repair.
  • Recharge Refrigerant: If necessary, the technician can recharge the refrigerant and seal any leaks to restore proper operation.

7. Verify Fan Operation

Ensure the indoor blower fan is operating correctly:

  • Fan Settings: Set the thermostat to “auto” mode rather than “on” to prevent continuous operation of the fan, which can lead to freezing.
  • Fan Inspection: If the fan is not running or is running at a slower speed, it may require repair or replacement by a professional.

8. Monitor System Operation

After addressing the issue and allowing the AC unit to thaw:

  • Restart the System: Once everything is clear and the ice has melted, turn the thermostat back to “cool” and the fan to “auto.” Gradually lower the temperature to test the system’s cooling capability.
  • Observe: Monitor the AC unit for any signs of re-freezing or abnormal operation. If issues persist, contact a professional HVAC technician for further diagnosis and repair.

9. Schedule Regular Maintenance

To prevent future incidents of AC freezing:

  • Annual Maintenance: Schedule annual maintenance with a qualified HVAC technician. They can inspect and tune up your system to ensure optimal performance and prevent issues like freezing.

By following these steps and addressing the underlying causes of AC freezing promptly, you can help restore proper operation and prolong the lifespan of your air conditioning system. If you’re unsure or if problems persist, it’s best to consult a professional HVAC technician for expert diagnosis and repair.


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