Troubleshooting Check Table - Mitsubishi Electric MUZ-GF60VE Service Manual

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
2.5 seconds OFF
4
11-time fl ash
5
2.5 seconds OFF
16-time fl ash
2.5 seconds OFF
6
'Outdoor unit
2-time fl ash
stops and 2.5 seconds OFF
7 restarts 3
minutes later'
is repeated.
3-time fl ash
2.5 seconds OFF
8
4-time fl ash
2.5 seconds OFF
9
5-time fl ash
2.5 seconds OFF
10
8-time fl ash
2.5 seconds OFF
11
10-time fl ash
2.5 seconds OFF
12
12-time fl ash
13
2.5 seconds OFF
13-time fl ash
2.5 seconds OFF
14
Outdoor unit 1-time fl ash
15
operates. 2.5 seconds OFF
3-time fl ash
2.5 seconds OFF
16
4-time fl ash
2.5 seconds OFF
17
7-time fl ash
2.5 seconds OFF
18
OBH635
Abnormal point/
Condition
Outdoor power sys- Overcurrent protection cut-out operates 3 consecutive times
tem within 1 minute after the compressor gets started.
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.
Outdoor control sys- Memory data cannot be read.
tem
(The upper lamp of OPERATION INDICATOR lamp of the in-
door unit lights up or fl ashes 7-time.)
Serial communica- The communication fails between the indoor and outdoor unit
tion for 3 minutes.
Stop valve/ Closed valve is detected.
Closed valve
4-way valve/ The 4-way valve does not work properly.
Pipe temperature The indoor coil thermistor detects an abnormal temperature.
Overcurrent protec- Large current fl ows into IGBT module (IC700).
tion
Discharge tempera- Temperature of discharge temperature thermistor exceeds
ture overheat protec- 116°C, compressor stops. Compressor can restart if discharge
tion temperature thermistor reads 100°C or less 3 minutes later.
Fin temperature Temperature of fi n temperature thermistor on the heat sink
/P.C. board tem- exceeds 75 ~ 80°C or temperature of P.C. board temperature
perature thermistor thermistor on the inverter P.C.board exceeds 70 ~ 75°C.
overheat protection
High pressure pro- Indoor coil thermistor exceeds 70°C in HEAT mode. Defrost
tection thermistor exceeds 70°C in COOL mode.
Compressor syn- Compressor current is abnormal.
chronous abnormal-
ity
Outdoor fan motor Outdoor fan has stopped 3 times in a row within 30 seconds
after outdoor fan start-up.
Compressor current Compressor current cannot be detected normally.
Bus-bar voltage Bus-bar voltage cannot be detected normally.
(DC)
Frequency drop by Current from power outlet is nearing breaker capacity.
current protection
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
Low discharge tem- Temperature of discharge temperature thermistor has been
perature protection 50°C or less for 20 minutes.
Condition
26
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.
• 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.
• Check stop valve.
• Refer to 11-5. "Check of R.V.
coil".
• Replace inverter P.C. board.
• Reconnect connector of compres-
sor.
• 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 compres-
sor.
• 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".
• 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".
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.
• 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 LEV".
• Check refrigerant circuit and refrig-
erant amount.