5 Reasons Your Mini-Split AC Won’t Come On

Your mini-split air conditioning system cools your home and keeps you comfortable. It can be frustrating if the unit fails to come on as it should, so troubleshooting is needed to determine the cause.

1. Thermostat Check

Always begin troubleshooting with a thermostat check. Verify that the thermostat is set to the cool and on settings. Then, try lowering it at least 10 to 15 degrees below the current room temperature. If the mini-split begins to blow cool air after adjusting the setting, then the issue could be as simple as a thermostat that needs to be recalibrated so that it reads the current room temperature accurately. 

2. Circuit Breaker 

A flipped circuit breaker or blown fuse can also cause your system to fail to operate completely. Ideally, each mini-split condensing unit should be wired into its own circuit. Failure to do so increases the chances of a blown breaker or an electrical overload in the system. You can troubleshoot the circuit by locating the proper breaker for the AC system in the circuit box. Turn the breaker to the off position, wait a moment, and flip it back on and see if the AC is now working properly.

3. Blocked Condensing Unit

The condensing unit is the outside portion of the mini-split system. You may have one or more condensing units, depending on the size and design of your AC system. Leaves, overgrown grass, and other debris can sometimes collect around the condensing unit, which leads to blocked airflow. The unit may go into an emergency shutdown mode if this occurs. Clear the condensing unit and make sure all filters are clean. You should be able to use the AC, although you may need to reset an emergency shutoff switch.

4. Refrigerant Leaks

Leaking refrigerant may not be immediately noticeable. Many common refrigerants tend to evaporate quickly, so you may not see the leak. Instead, the AC will begin to cool more poorly as the refrigerant level drops. Many mini-split units will go into a shutdown mode if there is no refrigerant left in the system, which is designed to prevent the unit from overheating. A technician will have to check the refrigerant levels, and then repair any leaks and recharge the unit with additional refrigerant. 

5. Failed Components

Not all mini-split failure options are something that a homeowner can easily troubleshoot. The electrical system within the unit, or issues with the fan and blower, may cause a unit to fail to turn on. The mini-split system must be inspected by a technician so that the exact cause of failure can be found. The damaged components are then either repaired or replaced.

Contact an air conditioning repair service if you are having issues with your mini-split unit.