11-3. TROUBLESHOOTING CHECK TABLE
No. Symptom LED
indication
Abnormal point/
Condition
Condition Remedy
1
Outdoor unit
does not op-
erate.
1-time fl ash every
2.5 seconds
Outdoor power sys-
tem
Overcurrent protection cut-out operates 3 consecutive times
within 1 minute after the compressor gets started.
• Reconnect connector of compres-
sor.
• Refer to 11-5. "How to check in-
verter/compressor".
• Check stop valve.
2
Outdoor thermistors Discharge temperature thermistor, fi n temperature thermistor,
defrost thermistor, P.C. board temperature thermistor, outdoor
heat exchanger temperature thermistor or ambient tempera-
ture thermistor shorts or opens during compressor running.
• Refer to 11-5. "Check of outdoor
thermistors".
3
Outdoor control sys-
tem
Memory data cannot be read.
(The upper lamp of OPERATION INDICATOR lamp of the in-
door unit lights up or fl ashes 7-time.)
• Replace inverter P.C. board.
4
6-time fl ash
2.5 seconds OFF
Serial communica-
tion
The communication fails between the indoor and outdoor unit
for 3 minutes.
• Check connection between the
inverter P.C. board and relay P.C.
board.
• Refer to 11-5. "How to check mis-
wiring and serial signal error.
5
11-time fl ash
2.5 seconds OFF
Stop valve/
Closed valve
Closed valve is detected.
• Check stop valve.
6
16-time fl ash
2.5 seconds OFF
4-way valve/
Pipe temperature
The 4-way valve does not work properly.
The indoor coil thermistor detects an abnormal temperature.
• Refer to 11-5. "Check of R.V.
coil".
• Replace inverter P.C. board.
7
17-time fl ash
2.5 seconds OFF
Outdoor refrigerant
system abnormality
A closed valve and air trapped in the refrigerant circuit are
detected based on the temperature sensed by the indoor and
outdoor thermistors and the current of the compressor.
• Check for a gas leak in a
connecting piping etc.
• Check the stop valve.
• Refer to 11-5. “Check of outdoor
refrigerant circuit”.
8
'Outdoor unit
stops and
restarts 3
minutes later'
is repeated.
2-time fl ash
2.5 seconds OFF
Overcurrent protec-
tion
Large current fl ows into IGBT module (IC700).
• Reconnect connector of compres-
sor.
• Refer to 11-5. "How to check in-
verter/compressor".
• Check stop valve.
9
3-time fl ash
2.5 seconds OFF
Discharge tempera-
ture overheat protec-
tion
Temperature of discharge temperature thermistor exceeds
116°C, compressor stops. Compressor can restart if discharge
temperature thermistor reads 100°C or less 3 minutes later.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 11-5. "Check of LEV".
10
4-time fl ash
2.5 seconds OFF
Fin temperature
/P.C. board tem-
perature thermistor
overheat protection
Temperature of fi n temperature thermistor on the heat sink
exceeds 75 ~ 80°C or temperature of P.C. board temperature
thermistor on the inverter P.C.board exceeds 70 ~ 75°C.
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 11-5. "Check of outdoor
fan motor".
11
5-time fl ash
2.5 seconds OFF
High pressure pro-
tection
Indoor coil thermistor exceeds 70°C in HEAT mode. Defrost
thermistor exceeds 70°C in COOL mode.
• Check refrigerant circuit and refrig-
erant amount.
• Check stop valve.
12
8-time fl ash
2.5 seconds OFF
Compressor syn-
chronous abnormal-
ity
Compressor current is abnormal.
• Reconnect connector of compres-
sor.
• Refer to 11-5. "How to check in-
verter/compressor".
13
10-time fl ash
2.5 seconds OFF
Outdoor fan motor
Outdoor fan has stopped 3 times in a row within 30 seconds
after outdoor fan start-up.
• Refer to 11-5. "Check of outdoor
fan motor.
• Refer to 11-5. "Check of inverter
P.C. board.
14
12-time fl ash
2.5 seconds OFF
Compressor current
Compressor current cannot be detected normally.
• Refer to 11-5. "How to check in-
verter/compressor".
15
13-time fl ash
2.5 seconds OFF
Bus-bar voltage
(DC)
Bus-bar voltage cannot be detected normally.
• It occurs with following case.
Instantaneous power voltage drop.
(Short time power failure)
• Refer to 11-5. "Check of power
supply".
• Refer to 11-5. "How to check in-
verter/compressor".
16
Outdoor unit
operates.
1-time fl ash
2.5 seconds OFF
Frequency drop by
current protection
Current from power outlet is nearing breaker capacity.
The unit is normal, but check the
following.
• Check if indoor fi lters are clogged.
• Check if refrigerant is short.
• Check if indoor/outdoor unit air cir-
culation is short cycled.
17
3-time fl ash
2.5 seconds OFF
Frequency drop by
high pressure pro-
tection
Temperature of indoor coil thermistor exceeds 55°C in HEAT
mode, compressor frequency lowers.
Frequency drop by
defrosting in COOL
mode
Indoor coil thermistor reads 8°C or less in COOL mode, com-
pressor frequency lowers.
18
4-time fl ash
2.5 seconds OFF
Frequency drop by
discharge tempera-
ture protection
Temperature of discharge temperature thermistor exceeds
111°C, compressor frequency lowers.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 11-5. "Check of LEV".
• Refer to 11-5. "Check of outdoor
thermistors".
19
7-time fl ash
2.5 seconds OFF
Low discharge tem-
perature protection
Temperature of discharge temperature thermistor has been
50°C or less for 20 minutes.
• Refer to 11-5. "Check of LEV".
• Check refrigerant circuit and refrig-
erant amount.
28
OBH635C
