Mitsubishi SRK100VNXWPZSX, Service Manual

Page: 170 / 202

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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
0 10 30 40 20 50
Temperature sensor resistance (k
Ω
)
Temperature (°C)
5k Ω 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: Insufficient refrigerant amount preventive control makes compressor stopped, if it judges insufficient 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 flash Keeps flashing
Keeps flashing
ON 7-time flash
Indoor display
RUN light TIMER light
Green LED
Yellow LED
Red LED
Outdoor unit
control PCB
Outdoor unit
inverter PCB
Insufficient refrigerant amount
or detection of service valve closure