Mitsubishi Electric M-SERIES, Manual

Page: 167 / 586

WALL-MOUNTED Inverter Heat Pump
M series
TROUBLESHOOTING
W
ALL-
MOUNTED
C-165
Troubleshooting check table
MUZ-FD25VA MUZ-GE25VA MUZ-GE42VA MUZ-GE60VA MUZ-HC25VA
MUZ-FD25VABH MUZ-GE25VAH MUZ-GE42VAH MUZ-GE71VA MUZ-HC35VA
MUZ-FD35VA MUZ-GE35VA MUZ-GE50VA MUZ-HC35VAB
MUZ-FD35VABH MUZ-GE35VAH MUZ-GE50VAH
No. Symptom LED indication
Abnormal point/
Condition
Condition
1
Outdoor unit
does not op-
erate.
1-time flash eve -
ry 2.5 seconds
Outdoor power
system
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 ( MUZ-HC )].
2
Outdoor thermistors Discharge temperature thermistor, fin temperature thermistor, defrost thermistor, P.C. board tem -
perature thermistor, outdoor heat exchanger temperature thermistor or ambient temperature ther-
mistor shorts or opens during compressor running.
3
Outdoor control
system
Nonvolatile memory data cannot be read properly.
(POWER ( MSZ-FD )/the upper ( MSZ-GE , MSZ-HC ) lamp of OPERATION INDICATOR lamp of the
indoor unit lights up or flashes 7-time.)
4
6-time flash
2.5 seconds OFF
Serial signal The communication fails between the indoor and outdoor unit for 3 minutes.
5
11-time flash
2.5 seconds OFF
Stop valve/
Closed valve
Closed valve is detected by compressor current.
6
14-time flash
2.5 seconds OFF
Outdoor unit
(Other abnormality)
Outdoor unit is defective.
7
'Outdoor unit
stops and
restarts 3
minutes later'
is repeated.
2-time flash
2.5 seconds OFF
Overcurrent protec-
tion
Large current flows into intelligent power module.
w
When overcurrent protection occurs whithin 10 seconds after compressor starts, compressor
restarts after 15 seconds ( MUZ-HC ).
8
3-time flash
2.5 seconds OFF
Discharge tem-
perature overheat
protection
Temperature of discharge temperature thermistor exceeds
116°C, compressor stops. Compressor can restart if discharge temperature thermistor reads 100°C
or less 3 minutes later.
9
4-time flash
2.5 seconds OFF
Fin temperature
/P.C. board tem-
perature thermistor
overheat protection
Temperature of fin temperature thermistor on the heat sink exceeds 75°C~ 80°C ( MUZ-FD , MUZ-
GE )/82°C ( MUZ-HC25 )/83°C ( MUZ-HC35 ) or temperature of P.C. board temperature thermistor on
the inverter P.C. board exceeds 70°C~ 75°C ( MUZ-FD , MUZ-GE )/81°C ( MUZ-HC25 )/85°C ( MUZ-
HC35 ).
10
5-time flash
2.5 seconds OFF
High pressure pro-
tection
Indoor coil thermistor exceeds 70°C in HEAT mode. Defrost thermistor exceeds 70°C in COOL
mode.
11
8-time flash
2.5 seconds OFF
Compressor syn-
chronous abnormal-
ity
The waveform of compressor current is distorted.
12
MUZ-FD, MUZ-GE
10-time flash
2.5 seconds OFF
Outdoor fan motor Outdoor fan has stopped 3 times in a row within 30 seconds after outdoor fan start-up.
13
12-time flash
2.5 seconds OFF
Each phase current
of compressor
Each phase current of compressor cannot be detected normally.
14
13-time flash
2.5 seconds OFF
DC voltage DC voltage of inverter cannot be detected normally.
15 Outdoor unit
operates.
1-time flash
2.5 seconds OFF
Frequency drop by
current protection
Current from power outlet is nearing breaker capacity.
PFC module stops due to overcurrent. (MUZ-GE60/71)
16
3-time flash
2.5 seconds OFF
Frequency drop by
high pressure pro-
tection
Temperature of indoor coil thermistor exceeds 55°C in HEAT mode, compressor frequency lowers.
Frequency drop by
defrosting in COOL
mode
Indoor coil thermistor reads 8°C or less in COOL mode, compressor frequency lowers.
17
4-time flash
2.5 seconds OFF
Frequency drop by
discharge tempera-
ture protection
Temperature of discharge temperature thermistor exceeds 111°C, compressor frequency lowers.
18
Outdoor unit
operates.
7-time flash
2.5 seconds OFF
Low discharge tem-
perature protection
Temperature of discharge temperature thermistor has been 50°C or less for 20 minutes.
19
8-time flash
2.5 seconds OFF
MUZ-FD, MUZ-
GE25/35/42/50, MUZ-HC
PAM protection
PAM: Pulse Ampli-
tude Modulation
The overcurrent flows into IGBT (Insulated Gate Bipolar transistor: TR821) or the bus-bar voltage
reaches 320 V or more, PAM stops and restarts.
MUZ-GE60/71
Zero cross detect-
ing circuit
Zero cross signal for PAM control cannot be detected.
20
9-time flash
2.5 seconds OFF
Inverter check
mode
The connector of compressor is disconnected, inverter check mode starts.
NOTE: 1. The location of LED is illustrated at the right figure.
2. LED is lighted during normal operation.
The flashing frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the flashing 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
LED
→
MUZ-FD,
MUZ-GE25/
35/42/50,
MUZ-HC
MUZ-GE
60/71
Flashing