What Causes an Air Conditioner to Freeze Up?

The symptoms of a frozen AC unit can be subtle, but because the consequences can be so serious, it’s important to stay alert to the signals your system may be sending. Running a frozen air conditioner without correcting the cause of the freeze-up can potentially lead to irreversible damage to the system’s compressor. That’s one important reason every homeowner should be diligent in watching for signs that indicate that the indoor evaporator coil is icing up.

When Your Air Conditioner Freezes Up: The Initial Signs

The following signs can indicate a freeze-up or other problem with your AC system:

• Sudden decrease in AC performance


• Reduced airflow from the system’s vents


• Unusually large amount of condensate drainage


• Continuously running system


• Uncomfortably warm indoor temperature

If you notice any of the above issues, don’t wait to investigate. Turn off your AC system immediately. Then proceed with your investigation.

Evidence that the Indoor Evaporator Coil is Frozen

During your investigation, you may notice one or more of the following signs that can help confirm your suspicion:

• Ice buildup on the outdoor refrigerant line


• Condensation forming on the surface of the indoor air handler


• Condensation forming on the surface of the condensate drain


• Unusually large amount of condensate drainage


• Ice buildup on the evaporator coil inside the air handler

Once you’ve verified that the evaporator coil is frozen, you’ll need to leave the AC system off until the coil thaws. This will generally take several hours. Turning on the fan — without using the air conditioning — can help speed up the process.

After the system has thawed completely, your wisest move would be to call an air conditioning specialist, such as Stiles Heating & Cooling, to inspect the system. Because some causes of a frozen coil are more serious or more technical than others, you may need an expert to diagnose and correct the problem.

Potential Causes of a Frozen Evaporator Coil

When an air conditioner freezes up, a number of issues may be at fault.

Air Flow Issues

The following situations can impede air flow to the evaporator coil in your AC system

• Dirty air filter


• Too-small return air ducts


• Blocked air ducts


• Closed or blocked registers


• Malfunctioning fan

Other Potential Problems

The following are several other situations that can cause your AC system to freeze up:

• Dirty or blocked evaporator coil


• Blocked drain pipe


• Refrigerant leak


• Low outdoor air temperature


• Too-low nighttime thermostat setting

A refrigerant leak is a serious issue that must be handled by a professional HVAC technician who is certified in the safe handling of AC refrigerant.

If you have any question about the seriousness of this or any other HVAC issue, call the experts at Stiles Heating & Cooling for prompt service throughout the Athens, GA and Anderson, SC areas.

http://stilesheatingcooling.com/what-causes-an-air-conditioner-to-freeze-up/