29
AC 198V to AC 264V?
Are there looseness or
disconnection of the indoor/
outdoor connecting wire?
Is anything displayed?
DC 17V to DC 28V?
Is “E8” displayed?
Can all the indoor
unit be operated?
Check the voltage between S2
and S3 on the terminal block of
the outdoor unit.
NO
YES
Not lighting.
Blinking.
NO
YES
NO
YES
Not displayed.
Displayed.
YES
NO
YES
NO
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.
Check the refrigerant address of
the outdoor unit. (SW1-3 to 1-6)
Check the looseness or disconnection
of the indoor/outdoor connecting wire.
Check the LED display of the
outdoor unit after turning on the
main power again.
Can the unit be restarted?
• Breaking or poor contact
of the indoor/outdoor
connecting wire
• Fix the breaking or poor
contact of the indoor/outdoor
connecting wire.
• Defective outdoor
controller circuit
board
• Replace the outdoor
controller circuit board.
• Normal.
Only the unit which
has the refrigerant
address “0” supplies
power to the remote
controller.
• Set the refrigerant
address to “0”. In case of
the multiple grouping
system, recheck the
refrigerant address again.
• Defective indoor
power board
• Replace the indoor
power board.
• Defective outdoor
power circuit board
• Replace the outdoor
power circuit board.
• Defective indoor
controller board
• Replace the indoor controller
board of the indoor unit which
doesn’t operate.
• Defective outdoor
controller circuit
board
• Replace the outdoor
controller circuit board.
• Influence of
electromagnetic noise
• Not abnormal.
There may be the influence
of electromagnetic noise.
Check the transmission wire
and get rid of the causes.
Symptoms: Nothing is displayed on the remote controller
Diagnosis flow
Cause
Inspection method and
troubleshooting
LED display of the indoor
controller board
LED1 :
LED2 :
LED3 : or
Check the status
of the indoor controller
board LED3 display.
Is the refrigerant
address “0”?
NO
YES
NO
YES
Is “EA” or “Eb”
displayed?
OCH525
