Mitsubishi Heavy Industries SRK60ZJX-S, Technical Manual

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244
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'10 • SR-T-091
E57
Insufficient refrigerant amount
or detection of service valve closure
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 return air
temperature thermistor
connectors OK?
NO
YES
NO
YES
Are the
characteristics of indoor heat
exchanger and/or return air
temperature thermistor
OK?
Is the low
pressure during operation
normal?
Indoor heat exchanger, return air temperature thermistor
Temperature-resistance characteristics
15
10
5
0 10 30 40 20 50
Temperature thermistor resistance (k
Ω
)
Temperature (°C)
5k Ω at 25°C
(Broken wire)
(Shot circuit)
Open fully.
Correct indoor heat
exchanger, return air
temperature thermistor
connector connections.
Defective indoor heat
exchanger, return air
temperature thermistor
➞
Replace.
Charge refrigerant.
Defective indoor control
PCB
➞
Replace. (Defective
indoor heat exchanger,
return air temperature
thermistor input circuits)
2. Error detection method
• Judge insufficient refrigerant
amount by detecting the
temperature differnce between
indoor heat exchanger (ThI-R)
and indoor return air (ThI-A).
3. Condition of Error displayed
When the insufficient refrigerant
amount is detected 3 times
within 60 minutes.
4. Presumable cause
• Defective indoor heat
exchanger temperature
thermistor
• Defective indoor return air
temperature thermistor
• Defective indoor control PCB
• Insufficient refregerant
amount
Note: When the compressor speed is 50 rps or under at 5 minutes after the start of compressor or the completion of defrosting, the low refrigerant protection control
judges, by detecting the difference between the indoor heat exchanger temperature (Th
I
-R) and the indoor return air temperature (Th
I
-A), that it is in the state of
gas low, and stops the compressor.
Cooling: Indoor return air temperature (Th
I
-A) – Indoor heat exchanger temperature (Th
I
-R) ≧ 4 deg
Heating: Indoor heat exchanger temperature (Th
I
-R) – Indoor return air temperature (Th
I
-A) ≦ 6 deg
Error code
Remote controller:
LED Green Red
Content
Indoor Keeps flashing Stays OFF