Transmission Error Between Indoor Units And Outdoor Units, Open Phase In Power Supply Wiring - Daikin VRV EMERION REYQ-AATJA Service Manual

Troubleshooting by Error Code
3.68 Transmission Error between Indoor Units and Outdoor
Units, Open Phase in Power Supply Wiring
Applicable
All indoor unit models
Models
All outdoor unit models
U4
Error Code
Method of Error
Microcomputer checks if transmission between indoor and outdoor units is normal.
Detection
Error Decision
Transmission is not carried out normally for a certain amount of time.
Conditions
Supposed
 Open phase in power supply wiring
Causes  Short circuit in indoor-outdoor or outdoor-outdoor transmission wiring (F1/F2), or wrong wiring
 Outdoor unit power supply is OFF
 System address does not match
 Defective indoor unit control PCB
 Defective outdoor unit main PCB
 Multi-tenant function is ON.
419
SiUS372201EB
Part 6 Service Diagnosis