Outdoor Unit Pcb Abnormality Or Signal Transmission Circuit Abnormality - Daikin G-Series Service Manual

SiBE12-933_A
4.24 Outdoor Unit PCB Abnormality or Signal Transmission
Circuit Abnormality
U4
Remote
Controller
Display
Method of 1. Detect within the program of the microcomputer that the program is operating normally.
2. When indoor-outdoor unit signal transmission can not be performed for more than 15
Malfunction
Detection
3. Detection of the presence or absence of zero-cross signal.
Malfunction 1. When the program of the microcomputer is in bad running order.
2. When indoor-outdoor unit signal transmission can not be performed for more than 15
Decision
Conditions
3. When zero-cross signal can not be detected for more than 10 seconds.
Supposed
Causes
Service Diagnosis
seconds.
seconds.
Display disabled due to power supply fault
Communication circuit fault in outdoor unit PCB
Out of control of microcomputer caused by external factors
Noise
Momentary voltage drop
Momentary power loss
Defective outdoor unit PCB
Defective thermal fuse in outdoor terminal board
Troubleshooting
209