Mitsubishi Electric MXZ-2D33VA Service Manual page 131

11-4. TROUBLESHOOTING CHECK TABLE
MXZ-2D
Indication
Symptom
No.
LED1(Red) LED2(Yellow)
Outdoor unit
1
Lighted Once
does not
operate.
2
Lighted Twice
3
Lighted 3 times
4
Lighted 4 times
5 Lighted 5 times
6 Lighted 7 times
7 Lighted 11 times
8 Lighted 17 times
'Outdoor
unit stops
Twice Not lighted
and restarts
9
3 minutes
later' is
repeated.
3 times Not lighted
10
11 4 times Not lighted
12 5 times Not lighted
13 9 times Not lighted
14
13 times Not lighted
15 8 times Not lighted
10 times Not lighted
16
Outdoor unit
operates.
17
Once Lighted
Twice Lighted
18
19
3 times Lighted
20 4 times
Lighted
OBH626K
Abnormal point / Condition
The indoor unit detects an abnormality in the LEV and drain pump.
LEV and drain pump
Overcurrent protection cut-out operates 3 consecutive times
within 1 minute after the compressor gets started.
Outdoor power system
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.
(MXZ-2D33VA, MXZ-2D40VA)
Closed valve
A closed valve and air trapped in the refrigerant circuit are detected
Outdoor refrigerant
based on the temperature sensed by the indoor and outdoor thermistors
system abnormality
and the current of the compressor.
14 A (MXZ-2D33VA)/18 A (MXZ-2D40VA, MXZ-2D42VA, MXZ-2D42VA2,
Overcurrent
MXZ-2D53VA/VAH, MXZ-2D53VA2/VAH2) current flows into intelligent
power module.
Discharge temperature exceeds 116°C during operation. Compressor can
Discharge temperature
protection restart if discharge temperature thermistor reads 100°C or less 3 minutes
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
The bus-bar voltage exceeds 430 V or falls to 50 V or below during
Bus-bar voltage
protection compressor operating.
Failure occurs 3 consecutive 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.
Primary current protection
The input current exceeds 8 A (MXZ-2D33VA)/ 10 A (MXZ-2D40VA,
MXZ-2D42VA, MXZ-2D42VA2, MXZ-2D53VA/VAH, MXZ-2D53VA2/VAH2).
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.
The discharge temperature exceeds 100°C during operation.
Discharge temperature
protection
The frequency of the compressor is kept 68 Hz (MXZ-2D33VA, MXZ-2D40
VA)/80 Hz (MSZ-2D42VA, MSZ-2D42VA2, MXZ-2D53VA/VAH, MXZ-
Low discharge
temperature protection 2D53VA2/VAH2) or more and the discharge temperature is kept under
50°C (COOL mode)/40°C (HEAT mode) for more than 40 minutes.
Condition
131
Remedy
Refer to 11-6. "Check of LEV".
Check the drain pump of the indoor unit.
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".
Replace the inverter P.C. board.
Refer to 11-6. "Check of outdoor thermistors".
Replace the inverter P.C. board.
Check the stop valve.
"Check of outdoor refrigerant circuit".
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.
Refer to 11-6. "Check of LEV".
"Check of outdoor fan motor".
Check the amount of gas and the refrigerant circuit.
Check the stop valve.
Replace the inverter P.C. board.
Refer to 11-6. "Check of outdoor fan motor".
Replace the inverter P.C. board.
Reconnect compressor connector.
Refer to 11-6. "How to check inverter/compressor".
Check the stop valve.
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.
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.