MITSUBISHI ELECTRIC MUY-GE09NA - Manual (Page 27)

27
10-3. TROUBLESHOOTING CHECK TABLE
No. Symptom LED indication
Abnormal point/
Condition
Condition Remedy
1
Outdoor
unit does
not oper-
ate.
1-time fl ash every
2.5 seconds
Outdoor power sys-
tem
Overcurrent protection stop is continuously performed 3 times
within 1 minute after the compressor gets started, or failure of re-
start of compressor has repeated 24 times.
Reconnect connector of compressor.
Refer to 10-5. "How to check inverter/
compressor".
Check stop valve.
•
•
•
2
Outdoor thermistors Discharge temperature thermistor, fi n temperature thermistor, de-
frost thermistor, outdoor heat exchanger temperature thermistor,
P.C. board temperature thermistor or ambient temperature therm-
istor shorts or opens during compressor running.
Refer to 10-5. "Check of outdoor
thermistors".
•
3
Outdoor control sys-
tem
Nonvolatile memory data cannot be read properly.
(POWER lamp of the indoor unit lights up or fl ashes 7 times.)
Replace inverter P.C. board. •
4
6-time fl ash
2.5 seconds OFF
Serial signal The communication fails between the indoor and outdoor unit for
3 minutes.
Refer to 10-5. "How to check miswir-
ing and serial signal error.
•
5
11-time fl ash
2.5 seconds OFF
Stop valve/
Closed valve
Closed valve is detected by compressor current. Check stop valve. •
6
14-time fl ash
2.5 seconds OFF
Outdoor unit
(Other abnormality)
Outdoor unit is defective. Refer to 10-2.2. "Flow chart of the de-
tailed outdoor unit failure mode recall
function".
•
7
'Outdoor
unit stops
and re-
starts 3
minutes
later' is
repeated.
2-time fl ash
2.5 seconds OFF
Overcurrent protec-
tion
Large current fl ows into intelligent power module.
When overcurrent protection occurs within 10 seconds after
compressor starts, compressor restarts after 15 seconds.
Reconnect connector of compressor.
Refer to 10-5. "How to check inverter/
compressor".
Check stop valve.
•
•
•
8
3-time fl ash
2.5 seconds OFF
Discharge tempera-
ture overheat 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 refrigerant circuit and refrigerant
amount.
Refer to 10-5. "Check of LEV".
•
•
9
4-time fl ash
2.5 seconds OFF
Fin temperature /P.C.
board temperature
thermistor overheat
protection
Temperature of fi n temperature thermistor on the heat sink ex-
ceeds 167 ~ 176°F (75 ~ 80°C) or temperature of P.C. board tem-
perature thermistor on the inverter P.C. board exceeds 158 ~ 167
°F (70 ~ 75°C).
Check around outdoor unit.
Check outdoor unit air passage.
Refer to 10-5. "Check of outdoor fan
motor".
•
•
•
10
5-time fl ash
2.5 seconds OFF
High pressure pro-
tection
(MUZ)
Temperature of indoor coil thermistor exceeds 158°F (70°C) in
HEAT mode. Temperature of outdoor heat exchanger temperature
thermistor exceeds 158°F (70°C) in COOL mode.
Check refrigerant circuit and refrigerant
amount.
Check stop valve.
•
•
11
8-time fl ash
2.5 seconds OFF
Compressor syn-
chronous abnormal-
ity
The waveform of compressor current is distorted. Reconnect connector of compressor.
Refer to 10-5. "How to check inverter/
compressor".
•
•
12
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 10-5. "Check of outdoor fan
motor.
Refer to 10-5. "Check of inverter P.C.
board.
•
•
13
12-time fl ash
2.5 seconds OFF
Each phase current
of compressor
Each phase current of compressor cannot be detected normally. Refer to 10-5. "How to check inverter/
compressor".
•
14
13-time fl ash
2.5 seconds OFF
DC voltage DC voltage of inverter cannot be detected normally. Refer to 10-5. "How to check inverter/
compressor".
•
15 Outdoor
unit oper-
ates.
1-time fl ash
2.5 seconds OFF
Frequency drop by
current protection
Current from power outlet is nearing Max. fuse size. The unit is normal, but check the follow-
ing.
Check if indoor fi lters are clogged.
Check if refrigerant is short.
Check if indoor/outdoor unit air circula-
tion is short cycled.
•
•
•
16
3-time fl ash
2.5 seconds OFF
Frequency drop by
high pressure protec-
tion
Temperature of indoor coil thermistor exceeds 131°F (55°C) in
HEAT mode, compressor frequency lowers.
Frequency drop by
defrosting in COOL
mode
Indoor coil thermistor reads 46°F (8°C) or less in COOL mode,
compressor frequency lowers.
17
4-time fl ash
2.5 seconds OFF
Frequency drop by
discharge tempera-
ture protection
Temperature of discharge temperature thermistor exceeds 232°F
(111°C), compressor frequency lowers.
Check refrigerant circuit and refrigerant
amount.
Refer to 10-5. "Check of LEV".
Refer to 10-5. "Check of outdoor
thermistors".
•
•
•
18
Outdoor
unit oper-
ates.
7-time fl ash
2.5 seconds OFF
Low discharge tem-
perature protection
Temperature of discharge temperature thermistor has been 122°F
(50°C) or less for 20 minutes.
Refer to 10-5. "Check of LEV".
Check refrigerant circuit and refrigerant
amount.
•
•
19
8-time fl ash
2.5 seconds OFF
PAM protection PAM:
Pulse Amplitude
Modulation
The overcurrent fl ows into IGBT (Insulated Gate Bipolar transis-
tor: TR821) or the bus-bar voltage reaches 320 V or more, PAM
stops and restarts.
This is not malfunction. PAM protection
will be activated in the following cases:
1 Instantaneous power voltage drop
(Short time power failure)
2 When the power supply voltage is high.
20
9-time fl ash
2.5 seconds OFF
Inverter check mode The connector of compressor is disconnected, inverter check
mode starts.
Check if the connector of the compres-
sor is correctly connected. Refer to
10-5. "How to check inverter/compres-
sor".
•
NOTE : 1. The location of LED is illustrated at the right fi gure. Refer to 10-6.1.
2. LED is lighted during normal operation.
The fl ashing frequency shows the number of times the LED blinks after every 2.5-second OFF. Flashing
(Example) When the fl ashing frequency is “2”.
ON
OFF
2.5-second OFF 2.5-second OFF
0.5-second ON 0.5-second ON
LED
Flashing →
Inverter P.C. board (Parts side)