How to Troubleshoot an Air Conditioner Wall Unit

Air conditioner wall units are placed in windows or walls.

Wall units, called unitary systems, are placed in a wall opening or a window, and have interior controls to adjust the temperature in the room. If issues occur with an air conditioner, some basic troubleshooting steps may fix the problem. Always unplug the unit before performing any cleaning or maintenance on the unit.

1. Make sure the power cord is plugged firmly into a grounded outlet. If the unit was turned off because of a power outage or other reasons, wait three minutes then restart the air conditioner. Reset the power cord or surge protector if necessary.

2. If the unit turns off even if the ambient temperature is warmer than the set temperature on the air conditioner, clean the condenser coil. Wait five minutes then restart the unit.

3. Allow 10 minutes after restarting for any temperature setting change to take place. If the air conditioner seems to be running continuously even though the air in the room is cool, ensure the unit is not placed next to another heat source, such as a television or lamp.

4. If the motor is running but no air is blowing, ensure there is nothing blocking the fan inside the air conditioner.

5. If the air conditioner does not seem to be cooling appropriately, adjust the temperature setting to a cooler temperature. Wait at least 10 minutes for the unit to adjust the temperature. Turn the unit off, unplug it, then clean the condenser coils and air filter if the unit continues to malfunction.

6. Defrost ice on the coils by setting the air conditioner to “Fan” and speed to "High." Once the coils have been defrosted, wipe away any remaining moisture and clean the air filter. Avoid using the air conditioner if the outside or room temperature is below 70 degrees Fahrenheit.