Troubleshooting Check Table - Mitsubishi Mr.Slim MUY-GE09NA Service Manual

10-3. TROUBLESHOOTING CHECK TABLE

No. Symptom LED indication
Outdoor 1-time fl ash every
unit does 2.5 seconds
1
not oper-
ate.
2
3
6-time fl ash
4
2.5 seconds OFF
11-time fl ash
5
2.5 seconds OFF
14-time fl ash
6 2.5 seconds OFF
'Outdoor 2-time fl ash
unit stops 2.5 seconds OFF
7
and re-
starts 3
minutes
3-time fl ash
later' is
2.5 seconds OFF
8
repeated.
4-time fl ash
2.5 seconds OFF
9
5-time fl ash
10 2.5 seconds OFF
8-time fl ash
11 2.5 seconds OFF
10-time fl ash
2.5 seconds OFF
12
12-time fl ash
13
2.5 seconds OFF
13-time fl ash
14
2.5 seconds OFF
Outdoor 1-time fl ash
15
unit oper- 2.5 seconds OFF
ates.
3-time fl ash
2.5 seconds OFF
16
4-time fl ash
2.5 seconds OFF
17
Outdoor 7-time fl ash
18 unit oper- 2.5 seconds OFF
ates.
8-time fl ash
2.5 seconds OFF
19
9-time fl ash
2.5 seconds OFF
20
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
2.5-second OFF
OFF
Abnormal point/
Condition
Outdoor power sys- Overcurrent protection stop is continuously performed 3 times
tem within 1 minute after the compressor gets started, or failure of re-
start of compressor has repeated 24 times.
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.
Outdoor control sys- Nonvolatile memory data cannot be read properly.
tem
(POWER lamp of the indoor unit lights up or fl ashes 7 times.)
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
Outdoor unit Outdoor unit is defective.
(Other abnormality)
Overcurrent protec- Large current fl ows into intelligent 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 241°F
ture overheat protec- (116°C), compressor stops. Compressor can restart if discharge
tion temperature thermistor reads 212°F (100°C) or less 3 minutes
later.
Fin temperature /P.C. Temperature of fi n temperature thermistor on the heat sink ex-
board temperature ceeds 167 ~ 176°F (75 ~ 80°C) or temperature of P.C. board tem-
thermistor overheat perature thermistor on the inverter P.C. board exceeds 158 ~ 167
protection °F (70 ~ 75°C).
High pressure pro- Temperature of indoor coil thermistor exceeds 158°F (70°C) in
tection HEAT mode. Temperature of outdoor heat exchanger temperature
thermistor exceeds 158°F (70°C) in COOL mode.
(MUZ)
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 normally.
of compressor
DC voltage DC voltage of inverter cannot be detected normally.
Frequency drop by Current from power outlet is nearing Max. fuse size.
current protection
Frequency drop by Temperature of indoor coil thermistor exceeds 131°F (55°C) in
high pressure protec- HEAT mode, compressor frequency lowers.
tion
Frequency drop by Indoor coil thermistor reads 46°F (8°C) or less in COOL mode,
defrosting in COOL compressor frequency lowers.
mode
Frequency drop by Temperature of discharge temperature thermistor exceeds 232°F
discharge tempera- (111°C), compressor frequency lowers.
ture protection
Low discharge tem- Temperature of discharge temperature thermistor has been 122°F
perature protection (50°C) or less for 20 minutes.
PAM protection PAM: The overcurrent fl ows into IGBT (Insulated Gate Bipolar transis-
Pulse Amplitude tor: TR821) or the bus-bar voltage reaches 320 V or more, PAM
Modulation stops and restarts.
Inverter check mode The connector of compressor is disconnected, inverter check
mode starts.
0.5-second ON
2.5-second OFF
Condition
0.5-second ON
27
Remedy
• Reconnect connector of compressor.
• Refer to 10-5. "How to check inverter/
compressor".
• Check stop valve.
• Refer to 10-5. "Check of outdoor
thermistors".
• Replace inverter P.C. board.
• Refer to 10-5. "How to check miswir-
ing and serial signal error.
• Check stop valve.
• Refer to 10-2.2. "Flow chart of the de-
tailed outdoor unit failure mode recall
function".
• Reconnect connector of compressor.
• Refer to 10-5. "How to check inverter/
compressor".
• Check stop valve.
• Check refrigerant circuit and refrigerant
amount.
• Refer to 10-5. "Check of LEV".
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 10-5. "Check of outdoor fan
motor".
• Check refrigerant circuit and refrigerant
amount.
• Check stop valve.
• Reconnect connector of compressor.
• Refer to 10-5. "How to check inverter/
compressor".
• Refer to 10-5. "Check of outdoor fan
motor.
• Refer to 10-5. "Check of inverter P.C.
board.
• Refer to 10-5. "How to check inverter/
compressor".
• Refer to 10-5. "How to check inverter/
compressor".
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.
• Check refrigerant circuit and refrigerant
amount.
• Refer to 10-5. "Check of LEV".
• Refer to 10-5. "Check of outdoor
thermistors".
• Refer to 10-5. "Check of LEV".
• Check refrigerant circuit and refrigerant
amount.
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.
• Check if the connector of the compres-
sor is correctly connected. Refer to
10-5. "How to check inverter/compres-
sor".
Inverter P.C. board (Parts side)
LED
Flashing →