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Symptoms: Nothing is displayed on the remote controller. 2
Check the voltage between S1 and S2 on the terminal block (TB4)
of the indoor unit which is used to connect the indoor unit and the outdoor unit.
198 to 264 VAC?
Yes
Check the status
of the indoor controller
board LED3 display.
Yes
Check the refrigerant address of
the outdoor unit. (SW1-3 to 1-6)
Is the refrigerant
address "0"?
Yes
Check the LED display of the
outdoor unit after turning on the
main power again.
Is anything displayed?
Is "EA" or "Eb"
displayed?
Yes
Check the voltage between S2
and S3 on the terminal block of
the outdoor unit.
17 to 28 VDC?
Yes
OCH653C
Diagnosis flow
No
No
Check the looseness or disconnection
of the indoor/outdoor connecting wire.
Are there looseness or
disconnection of the indoor/
outdoor connecting wire?
No
No
No
No
Is "E8" displayed?
Can the unit be restarted?
Can all the indoor
unit be operated?
No
Cause
Yes
• Breaking or poor
contact of the indoor/
outdoor connecting
wire
• Normal.
Only the unit which
has the refrigerant
address "0" supplies
power to the remote
controller.
• Defective outdoor
controller circuit
board
Yes
• Defective outdoor
controller circuit
board
No
No
• Defective indoor
controller board
Yes
• Influence of
electromagnetic noise
• Defective outdoor
power circuit board
• Defective indoor
power board
53
LED display of the indoor
controller board
LED1:
LED2:
LED3:
or
Inspection method and
troubleshooting
• Fix the breaking or poor
contact of the indoor/out-
door connecting wire.
• Set the refrigerant
address to "0". In the
case of the multiple
grouping system, recheck
the refrigerant address
again.
• Replace the outdoor
controller circuit board.
• Replace the outdoor
controller circuit board.
• Replace the indoor control-
ler board of the indoor unit
which does not operate.
• Not abnormal.
There may be
the influence of
electromagnetic noise.
Check the transmission
wire and eliminate the
causes.
• Replace the outdoor
power circuit board.
• Replace the indoor
power board.
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