An air conditioner that keeps turning itself off is usually following a setting, protecting itself, or losing power. Start with the remote: clear any off-timer, sleep or schedule. If the unit still shuts down, the common causes are dirty filters making it overheat or freeze, a blocked outdoor coil, a tripping circuit breaker, or a fault that the unit records as an error code. A unit that switches on and off every few minutes (“short cycling”) can also be oversized for the room or low on refrigerant.
Checks first
- Timers and schedules: clear the off-timer, sleep mode and any weekly timer or app schedule.
- Filters: clean them. A clogged filter can trigger an overheat or freeze protection shutdown.
- Outdoor unit: clear anything around it and check the fan spins while the unit runs.
- Error code: note any flashing lamp or code before you reset.
- Circuit breaker: if the breaker trips, reset it once. If it trips again, leave it off.
Causes and what each one needs
| Cause | Pattern | DIY or technician |
|---|---|---|
| Timer, sleep or schedule | Turns off at the same time each day | DIY |
| Dirty filters | Runs, then stops after a while; may ice up | DIY |
| Blocked or dirty outdoor coil | Shuts down on hot afternoons | DIY clear-around; technician to clean |
| Tripping breaker | Everything goes dead | Technician (electrical fault) |
| Oversized unit | Reaches temperature fast, cycles every few minutes | Technician to assess |
| Low refrigerant | Cycles, cools poorly, may ice | Technician (ARCtick-licensed) |
| Faulty sensor or control board | Random shutdowns; error codes | Technician |
| Condensate pump or float switch (some units) | Stops to prevent a water overflow | Technician |
If the breaker trips repeatedly or you smell burning, switch off at the isolator and leave the unit off until it has been checked.
Brand guides
For brand-specific codes, see Daikin error codes, Samsung error codes and Fujitsu error codes. For resets, see how to reset common faults.
Still cutting out? Book a technician, or go back to the troubleshooting hub.
For general advice on staying safe around electrical appliances at home, see Energy Safe Victoria.
Reviewed by AC repair and service specialist on 22 October 2026. How we write our articles