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The flashing frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the flashing frequency is “2”.
ON
OFF
2.5-second OFF
2.5-second OFF
0.5-second ON
0.5-second ON
Outdoor electronic control P.C. board(Parts side)
Lighting
LED2
LED1
10-3. TROUBLESHOOTING CHECK TABLE
MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA
No. Symptom
Indication
Abnormal point / Condition Condition Correspondence
LED1
(Red)
LED2
(Yellow)
1
Outdoor
unit does
not oper-
ate.
Lightning Twice Outdoor power system
IPM protection stop or lock protection stop is continuously
performed three times within 1 minute after the compressor
gets started, or converter protection stop or bus-bar voltage
protection stop is continuously performed 3 times within 3
minutes after start-up.
Check the connection of the compressor connect-
ing wire.
Refer to 10-5.
"How to check inverter/compres-
sor".
Refer to 10-5. "Check of compressor start failure".
Check the stop valve.
•
•
•
•
2 Lightning 3 times
Discharge temperature therm-
istor
A short circuit is detected in the thermistor during opera-
tion, or an open circuit is detected in the thermistor after 10
minutes of compressor start-up.
Refer to 10-5. "Check of outdoor thermistor". •
3 Lightning 4 times
Fin temperature thermistor
A short or open circuit is detected in the thermistor during
operation.
Refer to 10-5. "Check of outdoor thermistor". •
P.C. board temperature therm-
istor
Replace the outdoor electronic control P.C. board. •
4 Lightning 5 times
Ambient temperature thermis-
tor
A short or open circuit is detected in the thermistor during
operation.
Refer to 10-5. "Check of outdoor thermistor".•
Outdoor heat exchanger
temperature thermistor
A short circuit is detected in the thermistor during operation,
or an open circuit is detected in the thermistor after 5 minutes
(in cooling) and 10 minutes (in heating (MUZ)) of compressor
start-up.
Defrost thermistor (MUZ)
A short circuit is detected in the thermistor during operation,
or an open circuit is detected in the thermistor after 5 minutes
of compressor start-up.
5 Lightning 6 times Serial signal
The communication fails between the indoor and outdoor unit
for 3 minutes.
Refer to 10-5. "How to check miswiring and serial
signal error.
•
6 Lightning 7 times Nonvolatile memory data The nonvolatile memory data cannot be read properly. Replace the outdoor electronic control P.C. board. •
7 Lightning 8 times Current sensor
Current sensor protection stop is continuously performed
twice.
Replace the power board. •
8 Lightning 11 times
Communication error between
P.C. boards
The communication protection stop between boards is con-
tinuously performed twice.
Check the connecting wire between outdoor elec-
tronic control P.C. board and power board.
•
9 Lightning 12 times Zero cross detecting circuit
The protection stop of the zero cross detecting circuit is
continuously performed 10 times.
Check the connecting wire among outdoor elec-
tronic control P.C. board, noise fi lter P.C. board and
power board.
•
10
'Outdoor
unit stops
and restarts
3 minutes
later' is
repeated.
Twice Goes out
IPM protection
Overcurrent is detected after 30 minutes of compressor start-
up.
Reconnect compressor connector.
Refer to 10-5.
"How to check inverter/compres-
sor".
Refer to 10-5. "Check of compressor start failure".
Check the stop valve.
Check the power module (PAM module).
•
•
•
•
•
Lock protection
Overcurrent is detected within 30 minutes of compressor
start-up
11 3 times Goes out
Discharge temperature protec-
tion
Temperature of discharge temperature thermistor exceeds
241 °F (116 °C), compressor stops. Compressor can restart
if discharge temperature thermistor reads 212 °F (100 °C) or
less 3 minutes later.
Check the amount of gas and refrigerant circuit.
Refer to 10-5. "Check of LEV".
•
•
12 4 times Goes out
Fin temperature protection The fi n temperature exceeds 189 °F (87 °C) during operation.
Check refrigerant circuit and refrigerant amount.
Refer to 10-5. "Check of LEV".
•
•
P.C. board temperature pro-
tection
The P.C. board temperature exceeds 158 °F (70 °C) during
operation.
13 5 times Goes out High-pressure protection
The outdoor heat exchanger temperature exceeds 158 °F (70
°C) during cooling or indoor gas pipe temperature exceeds
158 °F (70 °C) during heating (MUZ).
Check around of gas and the refrigerant circuit.
Check of stop valve.
•
•
14 8 times Goes out Converter protection
A failure is detected in the operation of the converter during
operation.
Replace the power board. •
15 9 times Goes out
Bus-bar voltage protection (1)
The bus-bar voltage exceeds 400 V or falls to 200 V or below
during compressor operating.
Replace the power board.•
Bus-bar voltage protection (2)
The bus-bar voltage exceeds 400 V or falls to 50 V or below
during compressor operating.
16 13 times Goes out Outdoor fan motor
Failure occurs continuously three times within 30 seconds
after the fan gets started.
Refer to 10-5. "Check of outdoor fan motor". •
17 Lighting 8 times Current sensor protection
A short or open circuit is detected in the current sensor during
compressor operating.
Replace the power board. •
18 Lighting 11 times
Communication between P.C.
boards protection
Communication error occurs between the outdoor electronic
control P.C. board and power board for more than 10 sec-
onds.
Check the connecting wire between outdoor elec-
tronic control P.C. board and power board.
•
19 Lighting 12 times
Zero cross detecting circuit
protection
Zero cross signal cannot be detected while the compressor is
operating.
Check the connecting wire among outdoor elec-
tronic control P.C. board, noise fi lter P.C. board and
power board.
•
NOTE 1. The location of LED is illustrated at the right figure. Refer to 10-6.1.
2. LED is lighted during normal operation.