Mitsubishi Electric M Series Manual page 286

CEILING CASSETTE Inverter Heat Pump
MLZ-KA25VA MLZ-KA35VA MLZ-KA50VA
Troubleshooting check table
OPERATION INDICATOR
NOTE : Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
Abnormal
No.
Operation indicator lamp
point
Left lamp flashes.
0.5-second ON
Mis-Wiring
1 or serial
signal
0.5-second OFF
Outdoor
control
2
Left lamp lights up.
system
Indoor coil
Left lamp flashes.
thermistor
2-time flash
3
Room
tempera-
2.5-second OFF
ture
thermistor
Left lamp flashes.
3-time flash
Indoor fan
4
motor
2.5-second OFF
Left lamp flashes.
Indoor
4-time flash
5
control
system
2.5-second OFF
Left lamp flashes.
5-time flash
Outdoor
6 power
system
Left lamp flashes.
6-time flash
Outdoor
7
thermistors
Left lamp flashes.
7-time flash
Outdoor
8
control
system
Left lamp flashes.
9-time flash
Drain
9
pump
2.5-second OFF
Left lamp flashes.
14-time flash
Other
10
abnormality
2.5-second OFF
NOTE : When the indoor unit has started operation and the above failures are detected (the first detection after the power
ON), the indoor electronic control P.C. board turns OFF the indoor fan motor with OPERATION INDICATOR lamp
flashing.
C-284
· Flashing of OPERATION INDICATOR lamp (left-hand side lamp)
Lighted
indicates abnormalities.
Blinking
Not lighted
Symptom
Indoor unit
and outdoor
unit do not
operate.
Outdoor unit
does not
operate.
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
2.5-second OFF
Indoor unit
and outdoor
unit do not
operate.
2.5-second OFF
Indoor unit
and outdoor
unit do not
operate.
2.5-second OFF
Indoor unit
and outdoor
unit do not
operate.
Indoor unit
and outdoor
unit do not
operate.
Condition
When the serial signal from the outdoor unit is
not received for a maximum of 6 minutes.
When it cannot properly read data in the
nonvolatile memory of the inverter P.C. board
or of the outdoor electronic control P.C. board.
When the indoor coil or the room temperature
thermistor is shorts or opens circuit.
When the rotational frequency feedback
signal is not emitted during the indoor fan
operation.
When it cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.
The compressor stops 3 times consecutively
for over current protection or start-up failure
protection within 1 minute after start-up.
When the outdoor thermistors short or open
circuit during the compressor operation.
When it cannot properly read data in the
nonvolatile memory of the inverter P.C. board
or of the outdoor electronic control P.C. board.
• Float sensor is open.
• Float sensor detects abnormal water level.
An abnormality other than above mentioned is
detected.
M series