Mitsubishi Electric MUZ-HJ25VA-E2 Service Manual page 41

11-3. TROUBLESHOOTING CHECK TABLE
No. Symptom LED indication
Outdoor unit 1-time fl ash every
does not op- 2.5 seconds
1 erate.
2
3
6-time fl ash
4
2.5 seconds OFF
11-time fl ash
5
2.5 seconds OFF
16-time fl ash
6
2.5 seconds OFF
17-time fl ash
2.5 seconds OFF
7
'Outdoor unit 2-time fl ash
stops and 2.5 seconds OFF
8
restarts 3
minutes later'
is repeated.
3-time fl ash
2.5 seconds OFF
9
4-time fl ash
2.5 seconds OFF
10
5-time fl ash
11 2.5 seconds OFF
8-time fl ash
12 2.5 seconds OFF
10-time fl ash
2.5 seconds OFF
13
MUZ-HJ50/60/71VA
12-time fl ash
14
2.5 seconds OFF
13-time fl ash
15
2.5 seconds OFF
Outdoor unit 1-time fl ash
16
operates. 2.5 seconds OFF
3-time fl ash
2.5 seconds OFF
17
4-time fl ash
2.5 seconds OFF
18
5-time fl ash
19
2.5 seconds OFF
NOTE: 1. The location of LED is illustrated at the right fi gure. Refer to 11-6.1.
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.
(Example) When the fl ashing frequency is "2".
ON
2.5-second OFF
OFF
OBH648F
Abnormal point/
Condition
Outdoor power sys- Overcurrent protection cut-out operates 3 consecutive times
tem within 1 minute after the compressor gets started, or failure of
restart of compressor has repeated 24 times.
Outdoor thermistors Discharge temperature thermistor, fi n temperature thermistor,
defrost thermistor, P.C. board temperature thermistor or out-
door heat exchanger temperature thermistor shorts or opens
during compressor running.
Outdoor control sys- Nonvolatile memory data cannot be read properly.
tem
(The upper lamp of OPERATION INDICATOR lamp of the in-
door unit lights up or fl ashes 7-time.)
Serial signal The communication fails between the indoor and outdoor unit
for 3 minutes.
Stop valve/ Closed valve is detected by compressor current.
Closed valve
4-way valve/ The 4-way valve does not work properly.
Pipe temperature The indoor coil thermistor detects an abnormal temperature.
Outdoor refrigerant A closed valve and air trapped in the refrigerant circuit are
system abnormality detected based on the temperature sensed by the indoor and
outdoor thermistors and the current of the compressor.
Overcurrent protec- Large current fl ows into power module.
tion When overcurrent protection occurs within 10 seconds after
compressor starts, compressor restarts after 15 seconds.
Discharge tempera- Temperature of discharge temperature thermistor exceeds
ture overheat pro- 116 °C, compressor stops. Compressor can restart if discharge
tection temperature thermistor reads 100°C or less 3 minutes later.
Fin temperature Temperature of fi n temperature thermistor on the heat sink ex-
/P.C. board tem- ceeds 80 °C (HJ25/35)/75 °C (HJ50)/83 °C (HJ60/71) or tem-
perature thermistor perature of P.C. board temperature thermistor on the inverter
overheat protection P.C. board exceeds 78 °C (HJ25/35)/80 °C (HJ50/60/71).
High pressure pro- Indoor coil thermistor exceeds 70°C in HEAT mode. Defrost
tection thermistor exceeds 70 °C in COOL mode.
Compressor syn- The waveform of compressor current is distorted.
chronous abnormal-
ity
Outdoor fan motor Outdoor fan has stopped 3 times in a row within 30 seconds
after outdoor fan start-up.
Each phase current Each phase current of compressor cannot be detected nor-
of compressor mally.
DC voltage DC voltage of inverter cannot be detected normally.
Frequency drop by When the input current exceeds 5.4 A (HJ25)/6.1 A (HJ35)/
current protection 9.2 A (HJ50)/12.0 A (HJ60/71), compressor frequency lowers.
Frequency drop by Temperature of indoor coil thermistor exceeds 55 °C in HEAT
high pressure pro- mode, compressor frequency lowers.
tection
Frequency drop by Indoor coil thermistor reads 8 °C or less in COOL mode, com-
defrosting in COOL pressor frequency lowers.
mode
Frequency drop by Temperature of discharge temperature thermistor exceeds
discharge tempera- 111 °C, compressor frequency lowers.
ture protection
Outside temperature When the outside temperature thermistor shorts or opens,
thermistor protection protective operation without that thermistor is performed.
0.5-second ON
2.5-second OFF
Condition
0.5-second ON
41
Remedy
• Reconnect connector of compres-
sor.
• Refer to 11-5. "How to check in-
verter/compressor".
• Check stop valve.
• Refer to 11-5. "Check of outdoor
thermistors".
• Replace inverter P.C. board.
• Refer to 11-5. "How to check
miswiring and serial signal error.
• Check stop valve.
• Refer to 11-5. "Check of R.V. coil".
• Replace inverter P.C. board.
• Check for a gas leak in a
connecting piping etc.
• Check the stop valve.
• Refer to 11-5. "Check of outdoor
refrigerant circuit".
• Reconnect connector of compressor.
• Refer to 11-5. "How to check in-
verter/compressor".
• Check stop valve.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 11-5. "Check of LEV".
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 11-5. "Check of outdoor
fan motor".
• Check refrigerant circuit and refrig-
erant amount.
• Check stop valve.
• Reconnect connector of compressor.
• Refer to 11-5. "How to check in-
verter/compressor".
• Refer to 11-5. "Check of outdoor
fan motor.
• Refer to 11-5. "Check of inverter
P.C. board.
• Refer to 11-5. "How to check in-
verter/compressor".
• Refer to 11-5. "How to check in-
verter/compressor".
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
circulation is short cycled.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 11-5. "Check of LEV".
• Refer to 11-5. "Check of outdoor
thermistors".
• Refer to 11-5. Check of outdoor
thermistors.
Inverter P.C. board
LED
←
Flashing