Upper lamp blinks 0.5s ON/OFF — Miswiring or Serial Signal Error

What does Upper lamp blinks 0.5s ON/OFF mean?

The indoor unit's upper lamp blinks at 0.5-second intervals, indicating that the indoor and outdoor units are not operating. This usually means the serial signal from the outdoor unit is not being received for 6 minutes. It can also occur if the indoor unit was connected to a non-low-standby-power model outdoor unit after previously being connected to a low-standby-power model.

• Miswiring between the indoor and outdoor units
• No serial communication signal received from the outdoor unit
• Incompatibility issue after connecting to a different series of outdoor unit (e.g., MUZ-AP after MXZ series)

Click steps to track your progress.

1. 1

   Turn off the air conditioner at the main power supply breaker.

2. 2

   Wait for at least 30 seconds, then turn the main power supply back on.

3. 3

   Press the RESET button on your remote controller.

4. 4

   If the problem occurs after relocating the unit or connecting a different outdoor unit series, you may need to clear the memorized abnormal condition. To do this, first set up the failure mode recall function (refer to page 30).

5. 5

   With the remote controller pointed at the indoor unit, press the STOP/OPERATE (OFF/ON) button, then immediately press the EMERGENCY OPERATION switch to delete the memorized abnormal condition.

6. 6

   Finally, release the failure mode recall function by turning the power off and on again, or pressing the remote controller's RESET button.