Mitsubishi Electric MSZ-WR NA Series, Service Manual

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31
MUZ-WR18NA MUZ-WR24NA
The upper
lamp of the
OPERATION
INDICATOR
lamp
(Indoor unit)
Abnormal point
(Failure mode/protection)
LED indication
(Outdoor P.C. board)
Condition Remedy
Indoor/outdoor
unit failure
mode recall
function
Outdoor unit
failure mode
recall function
OFF None (Normal) — — — — —
1-time blink
2.5 seconds
OFF Indoor/outdoor communication,
receiving error
—
Any signals from the inverter P.C.
board cannot be received normally for
3 minutes. •Refer to 10-5. How
to check miswiring and
serial signal error.
○ ○
Indoor/outdoor communication,
receiving error
—
Although the inverter P.C. board
sends signal "0", signal "1" has been
received 30 consecutive times. •Refer to 10-5. How
to check miswiring and
serial signal error.
2-time blink
2.5 seconds
OFF Outdoor power system
—
Overcurrent protection cut-out
operates 3 consecutive times within
1 minute after the compressor gets
started.
• Reconnect
connectors.
• Refer to 10-5. "How
to check inverter/
compressor".
• Check stop valve.
○ ○
3-time blink
2.5 seconds
OFF Discharge temperature
thermistor 1-time blink every
2.5 seconds Thermistor shorts or opens during
compressor running.
• Refer to 10-5.
"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 blink
2.5 seconds OFF
P.C. board temperature
thermistor 4-time blink
2.5 seconds OFF
Ambient temperature
thermistor 2-time blink
2.5 seconds OFF
Outdoor heat exchanger
temperature thermistor
—
4-time blink
2.5 seconds
OFF Overcurrent 11-time blink
2.5 seconds OFF
Large current fl ows into the power
module (IC700).
• Reconnect
compressor connector.
• Refer to 10-5. "How
to check inverter/
compressor".
• Check stop valve.
—
○
Compressor synchronous
abnormality (Compressor start-
up failure protection) 12-time blink
2.5 seconds OFF Waveform of compressor current is
distorted.
• Reconnect
compressor connector.
• Refer to 10-5. "How
to check inverter/
compressor".
—
○
5-time blink
2.5 seconds
OFF Discharge temperature
—
Temperature of discharge temperature
thermistor exceeds 241°F (116°C),
compressor stops.
Compressor can restart if discharge
temperature thermistor reads
212°F (100°C) or less 3 minutes later.
• Check refrigerant
circuit and refrigerant
amount.
• Refer to 10-5. "Check
of LEV".
—
○
6-time blink
2.5 seconds
OFF High pressure
—
Temperature indoor coil thermistor
exceeds 158°F (70°C) in HEAT
mode. Temperature defrost thermistor
exceeds 158°F (70°C) in COOL mode.
• Check refrigerant
circuit and refrigerant
amount.
• Check stop valve.
—
○
7-time blink
2.5 seconds
OFF Fin temperature/ P.C. board
temperature 7-time blink
2.5 seconds OFF Temperature of the fi n temperature
thermistor on the inverter P.C. board
exceeds 167 - 187°F (75 - 86°C), or
temperature of P.C. board temperature
thermistor on the inverter P.C. board
exceeds 162 - 185°F (72 - 85°C).
• Check around outdoor
unit.
• Check outdoor unit air
passage.
• Refer to 10-5. "Check
of outdoor fan motor".
—
○
8-time blink
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 10-5. "Check
of outdoor fan motor".
Refer to 10-5. "Check
of inverter P.C. board".
—
○
9-time blink
2.5 seconds
OFF Nonvolatile memory data 5-time blink
2.5 seconds OFF Nonvolatile memory data cannot be
read properly.
• Replace the inverter
P.C. board.
○ ○
Power module (IC700) 6-time blink
2.5 seconds OFF The interface short circuit occurs in the
output of the power module (IC700).
The compressor winding shorts circuit.
• Refer to 10-5. "How
to check inverter/
compressor".
NOTE: Blinking patterns of this mode differ from the ones of
TROUBLESHOOTING CHECK TABLE (10-3.).
OBH819A