Mitsubishi Electric Mr.Slim MUZ-GC25NA - C1, Service Manual

Page: 29 / 64

29
MUZ-GC50NA-
C2
The left lamp of
OPERATION INDICATOR
lamp (Indoor unit)
Abnormal point
(Failure mode / protection)
LED indication
(Outdoor P.C. board)
Condition Correspondence
Indoor/outdoor
unit failure
mode recall
function
Outdoor unit
failure mode
recall function
OFF None (Normal) — — — — —
2-time fl ash
2.5 seconds
OFF
Outdoor power system
—
Overcurrent protection stop is
continuously performed 3 times within
1 minute after the compressor gets
started.
Reconnect connectors.
Refer to 9-5. "How
to check inverter/
compressor".
Check stop valve.
•
•
•
○ ○
3-time fl ash
2.5 seconds
OFF
Discharge temperature
thermistor
1-time fl ash every
2.5 seconds
Thermistor shorts or opens during
compressor running.
Refer to 9-5.
"Check of outdoor
thermistors".
Defective outdoor
thermistors can be
identi fi ed by checking
the blinking pattern of
LED.
•
•
○ ○
Defrost thermistor
Fin temperature thermistor 3-time fl ash
2.5 seconds OFF
P.C. board temperature
thermistor
4-time fl ash
2.5 seconds OFF
Ambient temperature
thermistor
2-time fl ash
2.5 seconds OFF
4-time fl ash
2.5 seconds
OFF
Overcurrent 11-time fl ash
2.5 seconds OFF
Large current fl ows into intelligent
power module.
Reconnect compressor
connector.
Refer to 9-5. "How
to check inverter/
compressor".
Check stop valve.
•
•
•
—
○
Compressor synchronous
abnormality (Compressor
start-up failure protection)
12-time fl ash
2.5 seconds OFF
Waveform of compressor current is
distorted.
Reconnect compressor
connector.
Refer to 9-5. "How
to check inverter/
compressor".
•
•
—
○
5-time fl ash
2.5 seconds
OFF
Discharge temperature
—
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.
Check refrigerant
circuit and refrigerant
amount.
Refer to 9-5. "Check
of LEV".
•
•
—
○
6-time fl ash
2.5 seconds
OFF
High pressure
—
Temperature indoor coil thermistor
exceeds 70°C in HEAT mode.
Temperature defrost thermistor
exceeds 70°C in COOL mode.
Check refrigerant
circuit and refrigerant
amount.
Check stop valve.
•
•
—
○
7-time fl ash
2.5 seconds
OFF
Fin temperature/ P.C. board
temperature
7-time fl ash
2.5 seconds OFF
Temperature of fi n temperature
thermistor on the inverter P.C. board
exceeds 75 ~ 80°C, or temperature of
P.C. board temperature thermistor on
the inverter P.C. board exceeds 70 ~
75°C.
Check around outdoor
unit.
Check outdoor unit air
passage.
Refer to 9-5. "Check
of outdoor fan motor".
•
•
•
—
○
8-time fl ash
2.5 seconds
OFF
Outdoor fan motor
—
Outdoor fan has stopped 3 times in a
row within 30 seconds after outdoor
fan start-up.
Refer to 9-5. "Check
of outdoor fan motor".
Refer to 9-5. "Check
of inverter P.C. board".
•
—
○
9-time fl ash
2.5 seconds
OFF
Nonvolatile memory data 5-time fl ash
2.5 seconds OFF
Nonvolatile memory data cannot be
read properly.
Replace the inverter
P.C. board.
•
○ ○
10-time fl ash
2.5 seconds
OFF
Discharge temperature
—
Temperature of discharge temperature
thermistor has been 50°C or less for
20 minutes.
Refer to 9-5. "Check
of LEV".
Check refrigerant
circuit and refrigerant
amount.
•
• —
○
11-time fl ash
2.5 seconds
OFF
DC voltage 8-time fl ash
2.5 seconds OFF
DC voltage of inverter cannot be
detected normally.
Refer to 9-5. "How
to check inverter/
compressor".
•
—
○
Each phase current of
compressor
9-time fl ash
2.5 seconds OFF
Each phase current of compressor
cannot be detected normally.
12-time fl ash
2.5 seconds
OFF
Overcurrent Compressor
open-phase
10-time fl ash
2.5 seconds OFF
Large current fl ows into intelligent
power module (IPM).
The open-phase operation of
compressor is detected.
The interphase short out occurs in the
output of the intelligent power module
(IPM).
The compressor winding shorts out.
Reconnect compressor
connector.
Refer to 9-5. "How
to check inverter/
compressor".
•
•
—
○
14-time fl ash
2.5 seconds
OFF
Stop valve (Closed valve) 14-time fl ash
2.5 seconds OFF
Closed valve is detected by
compressor current.
Check stop valve • ○ ○
NOTE : Blinking patterns of this mode differ from the ones of Troubleshooting check table (9-3.).