Transmission Error Between Indoor Unit And Outdoor Unit In The Same System - Daikin REYQ-TA Series Service Manual

Troubleshooting by Error Code
3.60 Transmission Error between Indoor Unit and Outdoor Unit
in the Same System
U9
Error Code
Applicable All indoor unit models
All outdoor unit models
Models
Method of Error Detect the error signal for the other indoor unit within the circuit by outdoor unit PCB.
Detection
Error Decision
The error decision is made on any other indoor unit within the system concerned
Conditions
Supposed
Causes
Troubleshooting
263
Transmission error between other indoor and outdoor units
Defective electronic expansion valve of other indoor unit
Defective indoor unit PCB of other indoor unit
Improper connection of transmission wiring between indoor and outdoor unit
Be sure to turn off the power switch before connecting or disconnecting
Caution connectors, or parts may be damaged.
Turn ON all indoor units.
All the units are
display U9.
YES
U9 has
been displayed for 2
minutes or more.
YES
NO
NO
SiUS371614E
Continue the operation.
Re-diagnose by display after
passage of 2 minutes or more.
The outdoor unit PCB indicated
by the error code U9 is normal.
Check for the indoor unit of other
system, and then conduct
troubleshooting by diagnosis
according to the Error Code
Flowchart.
Service Diagnosis