MITSUBISHI ELECTRIC MUZ-FD09NA- U1 - Manual (Page 20)

20
10-3. TROUBLESHOOTING CHECK TABLE
No. Symptom LED indication Abnormal point/
Condition
Condition Correspondence
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
restart of compressor has repeated 24 times.
Reconnect connector of compres-
sor.
Refer to 10-5. "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 or ambi-
ent temperature thermistor 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
miswiring 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
detailed outdoor unit failure mode
recall function".
•
7
'Outdoor unit
stops and
restarts 3 min-
utes 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 compres-
sor.
Refer to 10-5. "How to check in-
verter/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 dis-
charge temperature thermistor reads 212°F (100°C) or less 3
minutes later.
Check refrigerant circuit and refrig-
erant amount.
Refer to 10-5. "Check of LEV".
•
•
9
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 167 ~ 176°F (75 ~ 80°C) or temperature of P.C. board
temperature 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
Indoor coil thermistor exceeds 158°F (70°C) in HEAT mode.
Defrost thermistor exceeds 158°F (70°C) in COOL mode.
Check refrigerant circuit and refrig-
erant 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 compres-
sor.
Refer to 10-5. "How to check in-
verter/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 nor-
mally.
Refer to 10-5. "How to check in-
verter/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 in-
verter/compressor".
•
15 Outdoor unit
operates.
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
following.
Check if indoor fi lters are clogged.
Check if refrigerant is short.
Check if indoor/outdoor unit air cir-
culation is short cycled.
•
•
•
16
3-time fl ash
2.5 seconds OFF
Frequency drop by
high pressure pro-
tection
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 refrig-
erant amount.
Refer to 10-5. "Check of LEV".
Refer to 10-5. "Check of outdoor
thermistors".
•
•
•
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)