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

SiEN12-710A
4.24 Outdoor Unit PCB Abnormality or Signal Transmission
Circuit Abnormality
U4
Remote Control
Display
Method of
1. Detect within the programme of the microcomputer that the programme is operating
Malfunction
2. When indoor-outdoor unit signal transmission can not be performed for more than 15 sec.
Detection
3. Detection of the presence or absence of zero-cross signal.
Malfunction
1. When the programme of the microcomputer is in bad running order.
Decision 2. When indoor-outdoor unit signal transmission can not be performed for more than 15 sec.
3. When zero-cross signal can not be detected for more than 10 sec.
Conditions
Supposed
" Display disabled due to power supply fault
Causes " Communication circuit fault in outdoor unit PCB
" Out of control of microcomputer caused by external factors
" Defective outdoor unit PCB
" Defective thermal fuse in outdoor terminal board
Service Diagnosis
normally.
! Noise
! Momentary voltage drop
! Momentary power loss
Troubleshooting
143