Why Is my AC Condensing Unit Not Running?

The AC condensing unit is the part of an air conditioner system located outside a building, which consists of a system of coils that connect to units inside the building. When the condensing unit is not running, it does not produce air to cool or heat.


AC Condensing Units Control Indoor Temperatures

The condensing unit functions by compressing gas, or refrigerant, as it pumps through a system of coils. The refrigerant then becomes a high temperature, high pressure liquid, as it flows through copper tubing attached to a furnace.

The Refrigerant

The refrigerant expands and becomes a low temperature gas that absorbs heat as it passes through the home ductwork system. Moisture that condenses outside the coils is carried away by a drain.

Grass and Leaves

Grass and leaves built up around the AC condensing unit may cause it to stop running. Removing debris after mowing grass and cleaning the unit may return its functions.

Circuit Breaker

The AC condensing unit may not be running because the circuit breaker is off. You may simply need to go to the breaker box and flip the switch on.

Blocked Filter

A blocked outdoor unit may inhibit air flow, causing the home to not get enough air or heat. A monthly filter change encourages proper air flow.

Professional Help

It the unit does not run after simple changes, you may need to call a professional repair person, who will be able to detect mechanical issues restricting air flow.

About the Author

Based in Tucson, Ariz., Cicely A. Richard has been writing since 1996. Her articles have been published in the “Arizona Daily Star” newspaper and “ForeWord Magazine.” Richard earned Bachelor of Arts degrees in English and journalism from Louisiana State University. .