Mitsubishi Electric M Series Manual page 548

MULTI SYSTEM Inverter Heat Pump
Troubleshooting Check Table
MXZ-2B
Symptom Indication
No.
LED1(Red) LED2(Yellow)
Outdoor unit
1
Lighting Once
does not
operate.
2 Lighting Twice
3
Lighting 3 times
4
Lighting 4 times
5
Lighting 5 times
Lighting 7 times
6
7
Lighting 11 times
'Outdoor
unit stops
Twice Goes out
and restarts
8
3 minutes
later' is
repeated.
9 3 times Goes out
10 4 times Goes out
11 5 times Goes out
12 9 times Goes out
13 13 times Goes out
14 8 times Goes out
10 times Goes out
15
Outdoor unit
operates.
16
Once Lighting
Twice Lighting
17
18 3 times
Lighting
19
4 times
Lighting
C-546
Abnormal point/Condition
The indoor unit detects any abnormality in the LEV for drain.
LEV for drain
Overcurrent protection stop is continuously performed three times
Outdoor power system
within 1 minute after the compressor gets started.
A short circuit is detected in the thermistor during operation, or when an
Discharge temperature
open circuit is detected in the thermistor after 10 minutes of compressor
thermistor
start-up.
Fin temperature
thermistor
A short or open circuit is detected in the thermistor during operation.
P.C board temperature
thermistor
Ambient temperature
A short or open circuit is detected in the thermistor during operation.
thermistor
A short circuit is detected in the thermistor during operation, or when
Outdoor heat exchanger
an open circuit is detected in the thermistor after 5 minutes (in cooling)
temperature thermistor
and 10 minutes (in heating) of compressor start-up.
A short circuit is detected in the thermistor during operation, or when an
Defrost thermistor
open circuit is detected in the thermistor after 5 minutes of compressor
start-up.
The nonvolatile memory data cannot be read properly.
Nonvolatile memory data
Stop valve Closed valve is detected by compressor current.
Closed valve (MXZ-2B30VA, MXZ-2B40VA)
14 A (MXZ-2B30VA)/18 A (MXZ-2B40VA, MXZ-2B52VA) current flows
Overcurrent
into intelligent power module.
Discharge temperature Discharge temperature exceeds 116°C during operation. Compressor can
restart if discharge temperature thermistor reads 100°C or less 3 minutes
protection
later.
Fin temperature
The fin temperature exceeds 90°C during operation.
protection
P.C. board temperature
The P.C. board temperature exceeds 78°C during operation.
protection
The outdoor heat exchanger temperature exceeds 70°C during cooling
High-pressure
or indoor gas pipe temperature exceeds 70°C during heating.
protection
Bus-bar voltage The bus-bar voltage exceeds 430 V or falls to 50 V or below during
compressor operating.
protection
Failure occurs continuously three times within 30 seconds after the fan
Outdoor fan motor
gets started.
Current sensor
A short or open circuit is detected in the current sensor during
protection
compressor operating.
Compressor
The compressor does not synchronize with the operating power.
The input current exceeds 8 A (MXZ-2B30VA)/10 A (MXZ-2B40VA,
Primary current protection
MXZ-2B52VA).
Secondary current protection
The current of the compressor exceeds 17 A.
High-pressure protection
The indoor gas pipe temperature exceeds 45°C during heating.
Defrosting in cooling
The indoor gas pipe temperature falls 3°C or below during cooling.
Discharge temperature
The discharge temperature exceeds 100°C during operation.
protection
The frequency of the compressor is kept 68 Hz (MXZ-2B30VA, MXZ-
2B40VA)/80 Hz (MXZ-2B52VA) or more and the discharge temperature
Low discharge
is kept under 50°C (COOL mode)/40°C (HEAT mode) for more than
temperature protection
40 minutes.
Condition
M series