Buzz
1. U0 Error Code for Daikin Inverter Air Conditioners: Low Refrigerant Warning
– Low refrigerant or clogged refrigerant lines (installation error).
– Faulty temperature sensors (R4T, R7T).
– Low-pressure sensor malfunction.
– Fault in the outdoor unit board.
2. U1 Error Code for Daikin Inverter Air Conditioners: Phase Reversal, Phase Loss
– Power supply experiencing phase reversal.
– Power supply facing phase loss.
– Fault in the outdoor unit board.
3. U2 Error Code: Insufficient Power Supply Voltage or Rapid Voltage Drop
– Insufficient power supply.
– Immediate power supply failure.
– Phase loss.
– Inverter board malfunction.
– Compressor malfunction.
– Fault in the outdoor unit control board.
– Wiring fault in the main circuit.
– Faulty fan motor.
– Signal transmission wire malfunction.
4. U4 Error Code: Signal Transmission Issue Between Indoor and Outdoor Units
– Wiring between indoor-outdoor or outdoor-outdoor units is cut, short-circuited, or incorrectly connected (F1, F2).
– Power loss in the outdoor or indoor unit.
– Fault in the indoor unit board.
– Fault in the outdoor unit board.
– Incompatible address system.
5. U5 Error Code: Signal Transmission Issue Between Indoor Unit and Remote
– Check the transmission line between the indoor unit and the remote.
– Double-check settings if one indoor unit is using two remotes.
– Remote control board malfunction.
– Fault in the indoor unit board.
– Possible malfunctions due to interference.
6. U7 Error Code: Signal Transmission Issue Between Outdoor Units
– Check the connection between the outdoor unit and the C/H Control Adapter.
– Inspect the signal wire between outdoor units.
– Check the control board in the outdoor unit.
– Incorrect address (outdoor unit and C/H Control Adapter).
– Fault in the Cool/Heat Control Adapter.
– Incompatibility with the Cool/Heat Control Adapter.
7. U8 Error Code: Signal Transmission Issue Between Main and Sub Remotes
– Double-check the signal transmission wire between the main and sub remotes.
– Auxiliary control connection malfunction.
– Remote control board malfunction.
8. U9 Error Code: Signal Transmission Issue Between Outdoor and Indoor Units in the Same System
– Double-check the signal transmission wires inside and outside the system.
– Inspect the electronic expansion valve on the indoor unit of the system.
– Fault in the indoor unit board of the system.
– Connection issue between the outdoor unit and the indoor unit.
9. UA Error Code: Exceeding the Number of Indoor Units
– Double-check the number of indoor units.
– Fault in the outdoor unit board.
– Duplicate address on the central remote.
– Verify the system address and reconfigure.
– Incompatibility between the outdoor unit and the indoor unit.
– Failure to reset the outdoor unit board during replacement.
10. UE Error Code: Signal Transmission Issue Between Central Remote and Indoor Unit
– Check the signal between the indoor unit and the central control.
– Central control board malfunction.
– Fault in the indoor unit board.
– Signal transmission error from the master control.
11. UF Error Code: Incorrect Installation of the Cooling System, Incompatible Control Wires/Gas Lines.
– Check the signal between the indoor and outdoor units.
– Failure to perform a system diagnostic run.
– Fault in the indoor unit board.
– Check valve not open.
12. UH Error Code: System Malfunction, Undefined Gas System Address
– Check the signal between the outdoor-indoor units, outdoor-outdoor units.
– Fault in the outdoor unit board.
– Fault in the indoor unit board.
13. U3 Error Code: Malfunction Due to Unexecuted Diagnostic Operation
For U3 error code, you need to rerun the system diagnostic.
To check error codes on the Daikin inverter air conditioner, point the remote control towards the AC unit, then hold down the “Cancel” button for about 5 seconds. The control will display the error code '00' on the screen and blink. Proceed by pressing the “Cancel” button to cycle through the error codes. When you hear a long beep from the indoor unit and see the remote control responding, that indicates the air conditioner's error code.
