Mitsubishi Electric MXZ-2HA40VF, Service Manual

Page: 44 / 72

44
MXZ-3HA
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
LED1 LED2
OFF None (Normal) Lit Lit
2-time blink Outdoor power system Lit Lit Overcurrent protection cut-out operates 3 con-
secutive times within 1 minute after the com-
pressor 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 12-6.
"How to check inverter/compres-
sor".
• Check the stop valve.
○
3-time blink Discharge temperature thermistor Lit Once A thermistor shorts or opens during
compressor running. • Refer to 12-6. "Check of outdoor
thermistors".
○
Defrost thermistor Lit Once
Ambient temperature thermistor Lit Twice
Fin temperature thermistor Lit 3 times
P.C. board temperature thermis-
tor Lit 4 times • Replace the outdoor control P.C.
board.
Outdoor heat exchanger tem-
perature thermistor Lit 9 times • Refer to 12-6. "Check of outdoor
thermistors".
4-time blink Overcurrent Once Not lit
21 A current flows into power module.
• Reconnect compressor connector.
• Refer to 12-6. "How to check in-
verter/compressor".
• Check the stop valve.
—
5-time blink Discharge temperature Lit Lit The discharge temperature exceeds 115°C
during operation.
Compressor can restart if discharge tempera-
ture thermistor reads 80°C or less 3 minutes
later. • Check refrigerant circuit and refrig-
erant amount.
• Refer to 12-6. "Check of LEV". —
6-time blink High pressure Lit Lit The outdoor heat exchanger temperature ex-
ceeds 70°C during cooling or the indoor gas pipe
temperature exceeds 70°C during heating. • Check refrigerant circuit and refrig-
erant amount.
• Check the stop valve.
—
7-time blink Fin temperature 3 times Not lit
The fin temperature exceeds 88°C during op
-
eration.
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 12-6. "Check of outdoor
fan motor".
—
P.C. board temperature 4 times Not lit The P.C. board temperature exceeds 67°C
during operation.
8-time blink Outdoor fan motor Lit Lit A failure occurs 3 consecutive times within 30
seconds after the fan gets started. • Refer to 12-6. "Check of outdoor
fan motor".
—
9-time blink Outdoor control system Lit 5 times Nonvolatile memory data cannot be read prop-
erly.
• Replace the outdoor control P.C. board.
○
10-time blink Low discharge temperature
protection Lit Lit The frequency of the compressor is kept 80 Hz
or more and the discharge temperature is kept
under 39°C for more than 20 minutes. • Check refrigerant circuit and refrig-
erant amount.
• Refer to 12-6. "Check of LEV".
—
11-time blink Communication error
between P.C. boards Lit 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 Lit 7 times A short or open circuit is detected in the cur-
rent sensor during compressor operating.
—
—
Current sensor protection cut-out operates 2
consecutive times.
○
Zero cross detecting circuit 5 times Not lit 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
detecting circuit operates 10 consecutive
times.
○
Converter 5 times Not lit 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 5 times Not lit The bus-bar voltage exceeds 400 V or falls to
low level during compressor operating. • Check the voltage of power supply.
• Replace the outdoor control P.C.
board.
15-time blink LEV and drain pump Lit Lit The indoor unit detects an abnormality in
the LEV and drain pump. • Refer to 12-6. "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 (12-4.).
OBH828A