Daikin VRV4 air conditioner flashing fault code U9

Brand : Daikin VRV4
model : RXQ10AYM (CU)
model : FXMQ125PAVE
indoor error code : U9-01
outdoor error code: U4-01

Check if other indoor unit have Malfunction and confirm indoor unit mix is allowed.

Error Code U9
Transmission error between indoor and outdoor units in the same system.

Method Of Error
Detect the error signal for the other indoor unit within the circuit by outdoor unit PCB.

Error Decision Conditions
When the error decision is made on any other indoor unit within the system concerned.

Supposed Cause
1)Transmission error between other indoor and outdoor units.
2)Defective electronic expansion valve of other indoor unit.
3)Defective indoor unit PCB of other indoor unit.
4)Improper connection of transmission wiring between indoor and outdoor unit.

Remark.
At 2.45 minutes is press BS2 button 17 times.

Mode 1
[1-17] [1-18] [1-19] is check error code history.

[1-17] shows the latest Malfunction code.
[1-18] shows the 2nd last Malfunction code.
[1-19] shows the 3rd last Malfunction code.

when the latest Malfunction codes were reset by accident on an indoor unit user interface, they can be check again through this monitoring settings.

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