Has your central air conditioner suddenly stopped working? Check the inside of the air handler for signs of a freeze-up. If there has been a freeze-up, ice will have formed inside the unit and stopped the unit from functioning properly. If you do have ice, there are a couple of potential causes of the freeze-up that can get your system back up and running.

Note that you will want to leave both of these fixes in the hands of a trained HVAC repair professional, but it never hurts to understand the nature of the problem before you call the tech.

Refrigerant Problem

Improper levels of refrigerant—or having the wrong refrigerant type—can interfere with the proper function of your air conditioner and cause a freeze-up. Refrigerant starts as a gas in the condensing unit outside your house and is transformed into a liquid before it heads inside to the air handler.

Evaporator coils in the air handler change the refrigerant back into a gas. This change causes a chemical reaction that cools the surface of the coils. A nearby fan blows circulating air over the coils then back out your vents, and that is how your house cools down.

A problem with the refrigerant can cause these coils to become overly cold and freeze up, which prevents the next cycle of refrigerant from undergoing the proper chemical reaction to keep moving through the system.

If refrigerant is the problem, only a licensed HVAC technician can diagnose and fix the issue. Refrigerant is a strictly controlled chemical in most areas, and the fix should be left in the hands of a pro.

Air-Handler Problem

Your evaporator coils can freeze up even if the coils are clean and the refrigerant levels are normal. This can happen due to a failure of the nearby blower fan, which plays a key role in regulating the surface temperature of the coils. A lack of airflow can lead to the coils becoming overly cold and causing a freeze-up similar to that caused by improper refrigerant levels.

If the blower was the cause of the freeze-up, you might have noticed the output of cold air from your vents lessening or ceasing as the fan broke and before the coils had time to completely freeze. Ask an air-conditioning repair technician from a company such as Childers Enterprises Inc to examine the fan and its motor for electrical issues or parts failures and then replace the parts, if needed.