Outdoor Unit Pcb Abnormality Or Signal Transmission Error - Daikin 2MXS40H2V1B Service Manual

SiBE121123_A
7.3 Outdoor Unit PCB Abnormality or Signal Transmission
Error
U4
Error Code
Method of Error Detection within the program of the microcomputer that the program is in good running order.
Detection
Error Decision
Conditions
Supposed
Causes
Service Diagnosis
The program of the microcomputer does not work in order.
Signal transmission between the units cannot be performed for more than 15 seconds.
Zero-cross signal cannot be detected for more than 10 seconds.
Display disabled due to power supply fault
Momentary fall of voltage
Momentary power failure
Defective varistor
Defective fuse
Defective thermal fuse on outdoor terminal board
Defective terminal board
Defective outdoor unit PCB
Improper grounding work
Noise
Defective fan motor
Improper wiring between indoor and outdoor units
Defective indoor unit PCB
Troubleshooting for Outdoor Unit
182