Mitsubishi Electric MXZ-2C20NAHZ, Service Manual

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3. Table of outdoor unit failure mode recall function
The left lamp of
OPERATION IN-
DICATOR lamp
(Indoor unit)
Abnormal point
(Failure mode/protection)
LED indication
(Outdoor P.C.
board)
Condition Remedy
Indoor/
outdoor unit
failure mode
recall function
LED 1 LED 2
OFF None (Normal) Lighted Lighted
2-time fl ash Outdoor power system Lighted Lighted Overcurrent protection cut-out operates
3 consecutive times within 1 minute after
the compressor gets started, or converter
protection cut-out or bus-bar voltage
protection cut-out operates 3 consecutive
times within 3 minutes after startup.
• Check the connection of the com-
pressor connecting wire.
• Refer to 11-6.
"How to check inverter/compres-
sor".
• Check the stop valve.
○
3-time fl ash Discharge temperature thermistor Lighted Once A thermistor shorts or opens during
compressor running. • Refer to 11-6. "Check of outdoor
thermistors".
○
Defrost thermistor Lighted Once
Ambient temperature thermistor Lighted Twice
Fin temperature thermistor Lighted 3 times
P.C. board temperature thermistor Lighted 4 times • Replace the outdoor control P.C. board.
Outdoor heat exchanger tem-
perature thermistor Lighted 9 times • Refer to 11-6. "Check of outdoor
thermistors".
4-time fl ash Overcurrent Once Not
lighted
21 A ( MXZ-3C24/3C30/4C36NA, MXZ-3C24/
3C30/4C36NA2 )/28 A ( MXZ-5C42NA, MXZ-
2C20/3C24/3C30NAHZ, MXZ-5C42NA2,
MXZ-2C20/3C24/3C30NAHZ2
) current flows
into power module.
• Reconnect compressor connector.
• Refer to 11-6. "How to check in-
verter/compressor".
• Check the stop valve.
—
5-time fl ash Discharge temperature Lighted Lighted The discharge temperature exceeds 222.8°F
( MXZ-3C24/3C30/4C36NA, MXZ-3C24/3C30/
4C36NA2 )/240.8°F ( MXZ-2C20/3C24/3C30
NAHZ, 5C42NA, MXZ-2C20/3C24/3C30
NAHZ2, 5C42NA2
) during operation.
Compressor can restart if discharge tempera-
ture thermistor reads 203°F (
MXZ-3C24/3C30
/4C36NA, MXZ-3C24/3C30/4C36NA2 )/212°F
( MXZ-2C20/3C24/3C30NAHZ, 5C42NA,
MXZ-2C20/3C24/3C30NAHZ2, 5C42NA2 ) or
less 3 minutes later.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 11-6. "Check of LEV".
—
6-time fl ash High pressure Lighted Lighted The outdoor heat exchanger temperature ex-
ceeds 158°F during cooling or the indoor gas
pipe temperature exceeds 158°F during heating.
• Check refrigerant circuit and refrig-
erant amount.
• Check the stop valve.
—
7-time fl ash Fin temperature 3 times Not
lighted
The fin temperature exceeds 190°F ( MXZ-
3C24/3C30/4C36NA, MXZ-3C24/3C30/
4C36NA2
)/192°F ( MXZ-2C20/3C24/
3C30NAHZ, 5C42NA, MXZ-2C20/3C24/3C30
NAHZ2, 5C42NA2
) during operation.
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 11-6. "Check of outdoor
fan motor".
—
P.C. board temperature 4 times Not
lighted
The P.C. board temperature exceeds 152°F
(
MXZ-3C24/3C30/4C36NA, MXZ-3C24/3C30/
4C36NA2 )/189°F ( MXZ-2C20/3C24/3C30
NAHZ, 5C42NA, MXZ-2C20/3C24/3C30
NAHZ2, 5C42NA2
) during operation.
8-time fl ash Outdoor fan motor Lighted Lighted A failure occurs 3 consecutive times within
30 seconds after the fan gets started.
• Refer to 11-6. "Check of outdoor
fan motor".
—
9-time fl ash Outdoor control system Lighted 5 times Nonvolatile memory data cannot be read
properly.
• Replace the outdoor control P.C.
board.
○
10-time fl ash Low discharge temperature
protection Lighted Lighted The frequency of the compressor is kept 80
Hz or more and the discharge temperature is
kept under 102.2°F for more than 20 minutes.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 11-6. "Check of LEV".
—
11-time fl ash Communication error
between P.C. boards Lighted 6 times Communication error occurs between the out-
door control P.C. board and outdoor power P.C.
board for more than 10 seconds.
• Check the connecting wire between
outdoor control P.C. board and out-
door power P.C. board.
—
The communication between boards protec-
tion cut-out operates 2 consecutive times.
○
Current sensor Lighted 7 times A short or open circuit is detected in the cur-
rent sensor during compressor operating.
—
—
Current sensor protection cut-out oper-
ates 2 consecutive times.
○
Zero cross detecting circuit 5 times Not
lighted
Zero cross signal cannot be detected
while the compressor is operating. • Check the connecting wire among
outdoor control P.C. board and out-
door power P.C. board.
—
The protection cut-out of the zero cross de-
tecting circuit operates 10 consecutive times.
○
Converter 5 times Not
lighted
A failure is detected in the operation of the
converter during operation. • Check the voltage of power supply.
• Replace the outdoor power P.C.
board.
—
Bus-bar voltage 6 times Not
lighted
The bus-bar voltage exceeds 400 V or
falls to low level during compressor oper-
ating. • Check the voltage of power supply.
• Replace the outdoor control P.C.
board.
15-time fl ash LEV and drain pump Lighted Lighted The indoor unit detects an abnormality in
the LEV and drain pump.
• Refer to 11-6. "Check of LEV".
• Check the drain pump of the indoor unit.
—
NOTE : Blinking patterns of this mode differ from the ones of
TROUBLESHOOTING CHECK TABLE (11-4.).
OBH702E