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8-3. Troubleshooting check table
• The following indication applies regardless of shape of the indicator.
• Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
When the indoor unit has started operation and the following detection method has detected an abnormality
(the first detection after the power ON), the indoor electronic control P.C. board turns OFF the indoor fan motor with the
OPERATION INDICATOR lamp flashing.
Operation Indicator
Lighted
Not lighted
No.
1
2
4
6
SymptomOperation indicator lamp
Condition
Correspondence
Mis-Wiring
Outdoor
thermistor
Outdoor
control
system
Indoor coil
thermistor
3 minutes after power supply turns ON, when
serial signal is not received.
<Thermistor short>
Thermistors are abnormal when they short
after compressor start-up.
<Thermistor open>
Thermistors are abnormal when they open
after compressor start-up.
However, discharge temperature thermistor is
abnormal when open circuit is detected more
than 10 minutes after compressor start-up.
When it cannot properly read data in the
nonvolatile memory of the deicer P.C. board,
outdoor unit stops.
• Shortage of refrigerant
• Check the deicer P.C.
board.
Refer to "Check of outdoor
thermistor".
Refer to outdoor unit service
manual.
• Check the deicer P.C. board.
Refer to outdoor unit service
manual.
• Refer to 8-5. D "How to check
mis-wiring ".
3
Indoor fan
motor
Abnormal
point
Outdoor unit
does not
operate.
Room
temperature
thermistor
Detect Indoor coil/room temperature
thermistor short or open circuit every 8
seconds during operation.
• Refer to the characteristics of
main indoor coil thermistor,
sub indoor coil thermistor,
and room temperature
thermistor in 8-6.
Indoor fan repeats
12 seconds ON
and 3minutes OFF.
When the indoor
fan breaks, the fan
keeps stopping.
When rotational frequency feedback signal is
not emitting during 12-second indoor fan
operation.
• Refer to 8-5. A "Check of
indoor fan motor".
Indoor
control
system
When it cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
• Check the indoor electronic
control P.C. board.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
5
0.5-second ON
0.5-second OFF
2-time flash
2.5-second OFF
3-time flash
2.5-second OFF
4-time flash
2.5-second OFF
6-time flash
2.5-second OFF
7-time flash
2.5-second OFF
· Flashing of the OPERATION INDICATOR lamp (on the left-hand side)
indicates possible abnormalities.
· The OPERATION INDICATOR lamp (on the left-hand side) is lighting
during normal operation.
OB427B-1.qxp 07.5.16 3:30 PM Page 12