Mitsubishi Electric SEZ-KD VA Series, Service Manual

Page: 91 / 301

91
11-4. TROUBLESHOOTING CHECK TABLE
MXZ-2D
No.
1
2
3
4
5
6
8
9
10
11
12
13
14
15
Symptom
'Outdoor
unit stops
and restarts
3 minutes
later' is
repeated.
Primary current protection
Secondary current protection
High-pressure protection
Defrosting in cooling
3 times Lighted
Discharge temperature
protection
4 times
Lighted
Low discharge
temperature protection
• Check the refrigerant circuit and the refrigerant amount.
• Refer to 11-6.
"Check of LEV".
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6. "Check of LEV".
• Check the refrigerant circuit and the refrigerant amount.
These symptoms do not mean any abnormality of the
product, but check the following points.
• Check if indoor filters are clogged.
• Check if refrigerant is short.
• Check if indoor/outdoor unit air circulation is short cycled.
Twice Lighted
Once Lighted
The discharge temperature exceeds 100°C during operation.
The frequency of the compressor is kept 68 Hz (MXZ-2D33VA, MXZ-2D40
VA)/ 80 Hz (MSZ-2D42VA, MXZ-2D53VA/H) or more and the discharge
temperature is kept under 50°C (COOL mode)/40°C (HEAT mode) for
more than 40 minutes.
The input current exceeds 8 A (MXZ-2D33VA) / 10 A (MXZ-2D40VA,
MXZ-2D42VA, MXZ-2D53VA/H).
The current of the compressor exceeds 17 A.
The indoor gas pipe temperature exceeds 45°C during heating.
The indoor gas pipe temperature falls 3°C or below during cooling.
Outdoor unit
operates.
16
17
18
19
7
LED1(Red) LED2(Yellow)
Lighted Twice
Outdoor power system
Lighted 3 times
Discharge temperature
thermistor
Outdoor heat exchanger
temperature thermistor
Defrost thermistor
Lighted 7 times
Nonvolatile memory data
• Replace the inverter P.C. board.
Abnormal point / Condition Remedy
A short circuit is detected in the thermistor during operation, or when
an open circuit is detected in the thermistor after 5 minutes (in cooling)
and 10 minutes (in heating) of compressor start-up.
A short circuit is detected in the thermistor during operation, or when an
open circuit is detected in the thermistor after 5 minutes of compressor
start-up.
• Replace the inverter P.C. board.
Indication
Overcurrent protection cut-out operates 3 consecutive times
within 1 minute after the compressor gets started.
A short circuit is detected in the thermistor during operation, or when an
open circuit is detected in the thermistor after 10 minutes of compressor
start-up.
Condition
The nonvolatile memory data cannot be read properly.
Fin temperature
thermistor
P.C board temperature
thermistor
Lighted 4 times
Ambient temperature
thermistor
A short or open circuit is detected in the thermistor during operation.
A short or open circuit is detected in the thermistor during operation.
5 times Lighted
Overcurrent
3 times Not lighted
Discharge temperature
protection
Fin temperature
protection
P.C. board temperature
protection
High-pressure
protection
• Replace the inverter P.C. board.
Bus-bar voltage
protection
Not lighted
Outdoor fan motor
8 times Not lighted
Current sensor
protection
• Replace the inverter P.C. board.
Not lighted Compressor
• Refer to 11-6. "Check of outdoor fan motor".
• Reconnect compressor connector.
• Refer to 11-6.
"How to check inverter/compressor".
• Check the stop valve.
• Check the amount of gas and the refrigerant circuit.
• Check the stop valve.
• Check the amount of gas and the refrigerant circuit.
• Refer to 11-6.
"Check of LEV".
• Check the refrigerant circuit and the refrigerant amount.
• Refer to 11-6.
"Check of outdoor fan motor".
• Reconnect compressor connector.
• Refer to 11-6.
"How to check inverter/compressor".
• Check the stop valve.
Twice Not lighted
4 times Not lighted
5 times Not lighted
9 times Not lighted
14 A (MXZ-2D33VA) /18 A (MXZ-2D40VA, MXZ-2D42VA, MXZ-2D53VA/H )
current flows into intelligent power module.
The bus-bar voltage exceeds 430 V or falls to 50 V or below during
compressor operating.
Discharge temperature exceeds 116°C during operation. Compressor can
restart if discharge temperature thermistor reads 100°C or less 3 minutes
later.
The fin temperature exceeds 90°C during operation.
The P.C. board temperature exceeds 78°C during operation.
Failure occurs 3 consecutive times within 30 seconds after the fan
gets started.
A short or open circuit is detected in the current sensor during
compressor operating.
The compressor does not synchronize with the operating power.
The outdoor heat exchanger temperature exceeds 70°C during cooling
or indoor gas pipe temperature exceeds 70°C during heating.
Outdoor unit
does not
operate.
Lighted Once
LEV and drain pump
• Check the connection of the compressor connecting
wire.
• Refer to 11-6.
"How to check inverter/compressor".
• Check the stop valve.
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6. "Check of LEV".
• Check the drain pump of the indoor unit.
The indoor unit detects an abnormality in the LEV and drain pump.
Lighted 11 times
Stop valve
Closed valve Closed valve is detected by compressor current.
(MXZ-2D33VA, MXZ-2D40VA)
• Check the stop valve.
13 times
10 times
OBH626E