An A/C freeze during hot summer weather is never a good sign. A “freezing” central air conditioner refers to excessive ice formation in the evaporator coil. Sealed within the system air handler, the evaporator coil circulates refrigerant that extracts heat from household air passing through the coil passageways. Normal coil operating temperature is around 40 degrees, Fahrenheit. If the coil temperature drops below freezing, however, condensation on the coil turns to ice that quickly accumulates and eventually blocks all airflow. By the time that happens, serious damage to system components may have occurred, too.
Most causes of an A/C freeze require the training and expertise of a qualified HVAC service technician to diagnose and repair. However, one do-it-yourself alternative is worth a try. Low system airflow caused by a dirty or clogged air filter can cause coil temperature to drop below freezing and form ice. Check the condition of your air filter and change it if it appears dirty. If freezing recurs with a new filter, you’re out of DIY options. Call a professional.
Here are some other common issues a service tech will check and resolve:
Low Refrigerant Charge
When insufficient refrigerant circulates in the system, heat transfer into the coil declines. This causes coil temperature to drop into the freezing range, forming ice. Eventually, low refrigerant will cause the system to shut down automatically or, worse, potentially damage expensive components like the compressor. Low refrigerant is almost always caused by a small leak somewhere. A service technician has the training and specialized equipment to detect the leak, repair it and restore the refrigerant charge to specs.
Dirty, Dusty Coil
Accumulation of dirt and dust on evaporator coil surfaces also inhibits heat extraction and may cause the coil temperature to drop below freezing. Because the coil is sealed inside the air handler, cleaning it yourself isn’t an alternative. You need professional service, ASAP. A clean coil not only eliminates freezing, it provides better cooling performance and increased energy efficiency.
For fast service response to A/C freeze issues, contact the professionals at Beyer Boys.
Our goal is to help educate our customers in the greater San Antonio, Texas area about energy and home comfort issues (specific to HVAC systems).