Mitsubishi Electric MXZ-2A30VA, Service Manual

Page: 125 / 192

125
13-4. TROUBLESHOOTING CHECK TABLE
MXZ-2A
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 Lighting
Discharge temperature
protection
4 times
Lighting
Low discharge
temperature protection
• Check refrigerant circuit and refrigerant amount.
• Refer to 13-6.
"Check of LEV".
• Refer to 13-6. "Check of outdoor thermistors".
• Refer to 13-6. "Check of LEV".
• Check refrigerant circuit and 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 Lighting
Once Lighting
The discharge temperature exceeds 100°C during operation.
The frequency of the compressor is kept 80 Hz 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-2A30VA)/ 10 A (MXZ-2A40VA,
MXZ-2A52VA).
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)
Lighting Twice
Outdoor power system
Lighting 3 times
Discharge temperature
thermistor
Outdoor heat exchanger
temperature thermistor
Defrost thermistor
Lighting 7 times
Nonvolatile memory data
• Replace the outdoor electronic control P.C. board.
Abnormal point / Condition Correspondence
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 outdoor electronic control P.C. board.
Indication
Overcurrent protection stop is continuously performed three 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
Lighting 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 Lighting
Overcurrent
3 times Goes out
Discharge temperature
protection
Fin temperature
protection
P.C. board temperature
protection
High-pressure
protection
• Replace the power board.
Bus-bar voltage
protection
Goes out
Outdoor fan motor
8 times Goes out
Current sensor
protection
• Replace the power board.
Goes out Compressor
• Refer to 13-6. "Check of outdoor fan motor".
• Reconnect compressor connector.
• Refer to 13-6.
"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 refrigerant circuit.
• Refer to 13-6.
"Check of LEV".
• Check refrigerant circuit and refrigerant amount.
• Refer to 13-6. "Check of outdoor fan motor".
• Reconnect compressor connector.
• Refer to 13-6.
"How to check inverter/compressor".
• Check the stop valve.
Twice Goes out
4 times Goes out
5 times Goes out
9 times Goes out
23 A (MXZ-2A30VA- , MXZ-2A40VA, MXZ-2A52VA)/ 14 A (MXZ-2A
30VA- )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 continuously three 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 doesn't 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.
Lighting Once
LEV for drain
• Check the connection of the compressor connecting
wire.
• Refer to 13-6.
"How to check inverter/compressor".
• Check the stop valve.
• Refer to 13-6. "Check of outdoor thermistors".
• Refer to 13-6. "Check of outdoor thermistors".
• Refer to 13-6. "Check of outdoor thermistors".
• Refer to 13-6 "Check of LEV".
• Check the drain pump of the indoor unit.
The indoor unit detects any abnormality in the LEV for drain.
Lighting 11 times
Stop valve
Closed valve Closed valve is detected by compressor current.
(MXZ-2A30VA, MXZ-2A40VA - )
• Check the stop valve.
13 times
10 times
E2
E1
E2