Mitsubishi Electric SEZ-M-DA Series, Service Manual

Page: 101 / 130

101
MXZ-3F, 4F
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.
14-time blink Refrigerant leakage
(Sensor detection)
Lit Lit 1.Refrigerant leaks from the piping or the
heat exchanger in the indoor unit.
2.The following items are used around the
indoor unit.
• Spray (LP gas including Freon, and
whose main ingredient is propane and
butane)
• Aerosol insecticide (including ethanol)
• Air spray painting (including dichlo-
romethane)
• Charcoal (charcoal fire)
• Chemicals (such as ethanol)
• Turn off the power after the indoor
unit finishes its FAN operation.
(The FAN operation continues for 3
hours.)
• Check the indoor unit to detect the
part where refrigerant leaks.
• Repair the part where refrigerant
leaks.
• Turn on the power again.
• Replace the refrigerant sensor if
the problem is not fixed.
○
NOTE : Blinking patterns of this mode differ from the ones of
Troubleshooting check table (12-4.).
OBH790D