How to Troubleshoot My Ductless Mini-Split AC

Unplug the air conditioner to reset the connection if the mini-split isn't getting power. Plug the air conditioner back in after 10 seconds, and turn on the unit. If power still fails to flow through the unit, inspect the power cord for damage, such as kinks, frays or deep dents. If the power cord is damaged, replace it.

Locate the breaker box inside your home, and pinpoint the breaker that controls your mini-split system. Look at the breaker switch. If the switch is in the middle or off position, then the circuit is opened, and the breaker is tripped. Flip the switch back to the on position. If the unit still fails to turn on, press the reset button on the mini-split system plug. The button should remain compressed as you turn the unit on.

Remove furniture or curtains from the front of the unit if airflow is hindered. The unit can't suck in air through the intake grille if the grille is blocked. Remove furniture, such as chairs or couches, from the front of the unit.

Grab the front panel with your hand, and lift it up if airflow from the unit is restricted. The air filter might be dirty. Lift the filter from the slot behind the front panel. Use a vacuum cleaner to remove dirt and debris from the filter until it's clean. Reinsert the filter into the slot, and close the front panel.

Set the thermostat control to a high temperature and the fan to high if the system has frozen over and is keeping air from blowing through the vents. The warmer air will melt the ice that might have been created from cold outside air. After the unit is thawed, keep the temperature high and the fan on low.

Inspect the room for openings, such as open windows, holes in the wall or open floor vents, if cold air blows from the unit but doesn't cool the room. There might be leaks in the room that allow the cold air to escape. Close up any openings inside the room, and turn off heat-producing appliances.