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9-4. TROUBLESHOOTING CHECK TABLE
Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
When the indoor unit has started operation and detected an abnormality of the following condition (the first detection after the
power ON), the indoor fan motor turns OFF and OPERATION INDICATOR lamp blinks.
• The following indicator applies regardless of shape of the indication.
OPERATION INDICATOR
Abnormal
No.
Operation indicator lamp
point
Left lamp blinks.
0.5-second ON
Miswiring
1
or serial
signal
0.5-second OFF
Left lamp blinks.
Indoor coil
2-time blink
thermistor
2
Room
temperature
2.5-second OFF
thermistor
Left lamp blinks.
3-time blink
Indoor fan
3
motor
2.5-second OFF
Left lamp blinks.
4-time blink
Indoor
4
control
system
Left lamp blinks.
5-time blink
Outdoor
5
power
system
Left lamp blinks.
6-time blink
Outdoor
6
thermistors
Left lamp blinks.
7-time blink
Outdoor
7
control
system
Left lamp blinks.
14-time blink or more
Other
2.5-second OFF
8
abnormality
*2 on 9-3
Outdoor
9
control
Left lamp lights up.
system
OBH736C
Lit
Blinking
Not lit
Symptom
2.5-second OFF
Indoor unit and
outdoor unit do
not operate.
2.5-second OFF
2.5-second OFF
2.5-second OFF
Outdoor unit
does not
operate.
Condition
The serial signal from the outdoor unit is not
received for 6 minutes.
The indoor coil or the room temperature
thermistor is short or open circuit.
The rotational frequency feedback signal is
not emitted during the indoor fan operation.
It cannot properly read data in the nonvolatile
memory of the indoor electronic control P.C.
board.
It consecutively occurs 3 times that the com-
pressor stops for overcurrent protection or
start-up failure protection within 1 minute
after start-up.
The outdoor thermistors short or open circuit
during the compressor operation.
It cannot properly read data in the nonvolatile
memory of the inverter P.C. board or the out-
door electronic control P.C. board.
An abnormality other than the above is
detected.
An abnormality of the indoor thermistors, the
defrost thermistor or ambient temperature
thermistor is detected.
It cannot properly read data in the nonvolatile
memory of the inverter P.C. board or the out-
door electronic control P.C. board.
23
Remedy
• Refer to 9-6.
"How to check
miswiring and serial signal
error".
• Refer to the characteristics of
indoor coil thermistor, and the
room temperature thermistor
(9-7.).
• Refer to 9-6.
"Check of
indoor fan motor".
• Replace the indoor electronic
control P.C. board.
• Refer to "How to check of
inverter/compressor".
Refer to outdoor unit service
manual
• Check the stop valve.
• Refer to "Check of outdoor
thermistor".
Refer to outdoor unit service
manual.
• Replace the inverter P.C. board
or the outdoor electronic control
P.C. board.
Refer to outdoor unit service
manual.
• Check the stop valve.
• Check the 4-way valve.
• Confirm the abnormality in
detail using the failure mode
recall function for outdoor unit.
• Refer to "TEST POINT DIA-
GRAM AND VOLTAGE" on the
service manual of indoor and
outdoor unit for the characteris-
tics of the thermistors. (Do not
start the operation again with-
out repair to prevent hazards.)
• Check the blinking pattern of
the LED on the inverter P.C.
board or the outdoor electronic
control P.C. board.
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