Mitsubishi FDU140VNXWVH - Page 170

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169
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'20 • PAC-SM-351
E57
1. Applicable model
5. Troubleshooting
All models
Diagnosis Countermeasure
NO
YES
NO
YES
Is the
service valve fully
opened?
Are the
connections of indoor
heat exchanger and/or room
temperature sensor
connectors OK?
NO
YES
NO
YES
Are the
characteristics of indoor heat
exchanger and/or room
temperature sensor
OK?
For the characteristics of indoor heat exchanger,
room temperature sensor
, see the following graph.
Is the low
pressure during operation
normal?
Indoor heat exchanger, room temperature sensor
Temperature-resistance characteristics
15
10
5
010304020 50
Temperature sensor resistance (k
Ω)
Temperature (°C)
5kΩ at 25°C
(Broken wire)
(Short-circuit)
Open fully.
Correct indoor heat
exchanger, room
temperature sensor
connector connections.
Defective indoor
heat exchanger, room
temperature sensor
➞
Replace.
Charge refrigerant.
Defective indoor unit
control PCB
➞
Replace.
(Defective indoor
heat exchanger, room
temperature sensor input
circuits)
2. Error detection method
• Judge insufficient refrigerant
amount by detecting the
temperature differnce between
indoor heat exchanger (Th2)
and indoor room (Th1).
• It detects at initial startup in
cooling or dehumidifying
mode after power ON.
3 . Condition of error displayed
Anomalous stop at initial
detection
4. Presumable cause
• Defective indoor heat
exchanger temperature sensor
• Defective indoor room
temperature sensor
• Defective indoor unit control
PCB
• Insufficient refrigerant amount
Note: Insufcient refrigerant amount preventive control makes compressor stopped, if it judges insufcient refrigerant amount by detecting the
temperature difference between indoor heat exchanger (Th2) and room temperature (Th1) for 5 minutes after compressor ON in cooling
or dehumidifying mode and for 9 minutes after compressor ON in heating mode. [ in cooling mode: (Th1)-(Th2)<4degC, in heating mode:
(Th2)-(Th1)<4degC]
Error code
Remote control:
Content
1-time flashKeeps flashing
Keeps flashing
ON7-time flash
Indoor display
RUN light TIMER light
Green LED
Yellow LED
Red LED
Outdoor unit
control PCB
Outdoor unit
inverter PCB
Insufcient refrigerant amount
or detection of service valve closure