Troubleshooting by Remote Controller Si20-701_B
375
3.92
U4
or
UF
Transmission Error
(Between Indoor Unit and
Outdoor Unit)
Remote Controller Display
U4
or
UF
Applicable Models
R(Y)-FU
Method of Error Detection
Micro-computer checks if transmission between indoor
and outdoor units is normal.
Error Decision Conditions
When transmission is not carried out normally for a
certain amount of time
Supposed Causes
îš„ Wiring indoor-outdoor transmission wire is incorrect.
îš„ Defective indoor unit PCB
îš„ Defective outdoor unit PCB
îš„ External factor (Noise, etc.)