Mitsubishi Electric Mr.Slim MUZ-GC25NA - C1 Service Manual page 33

MUZ-GC50NA-
C2
No. Symptom LED indication
Outdoor unit 1-time fl ash every
does not oper- 2.5 seconds
1 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
2.5 seconds OFF
6
'Outdoor unit 2-time fl ash
stops and 2.5 seconds OFF
7 restarts 3 min-
utes later' is
repeated.
3-time fl ash
8 2.5 seconds OFF
4-time fl ash
2.5 seconds OFF
9
5-time fl ash
10 2.5 seconds OFF
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
14
2.5 seconds OFF
15 Outdoor unit 1-time fl ash
operates. 2.5 seconds OFF
3-time fl ash
2.5 seconds OFF
16
4-time fl ash
2.5 seconds OFF
17
Outdoor unit 7-time fl ash
operates. 2.5 seconds OFF
18
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 9-6.1.
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
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
restart of compressor has repeated 24 times.
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.
Outdoor control sys- Nonvolatile memory data cannot be read properly.
tem
(The left lamp of OPERATION INDICATOR lamp of the indoor
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
Outdoor unit Outdoor unit is defective.
(Other abnormality)
Overcurrent protec- Large current fl ows into intelligent power module.
tion
Discharge tempera- Temperature of discharge temperature thermistor exceeds 116
ture overheat protec- °C, compressor stops. Compressor can restart if discharge
tion temperature thermistor reads 100°C or less 3 minutes later.
Fin temperature /P.C. Temperature of fi n temperature thermistor on the heat sink
board temperature exceeds 75 ~ 88°C or temperature of P.C. board temperature
thermistor overheat thermistor on the inverter P.C.board exceeds 72 ~ 82°C.
protection
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 Current from power outlet reaches the protection current, and
current protection 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 111
discharge tempera- °C, compressor frequency lowers.
ture protection
Low discharge tem- Temperature of discharge temperature thermistor has been 50
perature protection °C or less for 20 minutes.
PAM protection PAM The overcurrent fl ows into IGBT (Insulated Gate Bipolar tran-
: Pulse Amplitude sistor : TR821) or when the bus-bar voltage reaches 320 V or
Modulation more, PAM 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
33
Correspondence
• Reconnect connector of compres-
sor.
• Refer to 9-5. "How to check in-
verter/compressor".
• Check stop valve.
• Refer to 9-5. "Check of outdoor
thermistors".
• Replace inverter P.C. board.
• Refer to 9-5. "How to check mis-
wiring and serial signal error.
• Check stop valve.
• Refer to 9-2.2. "Flow chart of the
detailed outdoor unit failure mode
recall function".
• Reconnect connector of compres-
sor.
• Refer to 9-5. "How to check in-
verter/compressor".
• Check stop valve.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 9-5. "Check of LEV".
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 9-5. "Check of outdoor
fan motor".
• Check refrigerant circuit and refrig-
erant amount.
• Check stop valve.
• Reconnect connector of compres-
sor.
• Refer to 9-5. "How to check in-
verter/compressor".
• Refer to 9-5. "Check of outdoor
fan motor.
• Refer to 9-5. "Check of inverter
P.C. board.
• Refer to 9-5. "How to check in-
verter/compressor".
• Refer to 9-5. "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 9-5. "Check of LEV".
• Refer to 9-5. "Check of outdoor
thermistors".
• Refer to 9-5. "Check of LEV".
• Check refrigerant circuit and refrig-
erant amount.
This is not malfunction. PAM protec-
tion 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 com-
pressor is correctly connected.
Refer to 9-5. "How to check in-
verter/compressor".
Inverter P.C. board(Parts side)
LED
Flashing →