Mitsubishi Electric FDT125VNVF Technical Manual page 451

Indoor display
Error code
E57
Remote controller:
inverter PCB
1. Applicable model
All models
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).
• 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
thermistor
• Defective indoor return air
temperature thermistor
• Defective indoor control PCB
• Insufficient refregerant
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 (ThI-R) and return air temperature (ThI-A) for 1 minute after compressor ON in
cooling or dehumidifying mode and for 9 minutes after compressor ON in heating mode. [ in cooling mode: (ThI-A)-(ThI-R)>4degC, in
heating mode: (ThI-R)-(ThI-A)<4degC]
RUN light
7 times flash
Green LED
Outdoor
control PCB
Keeps flashing
Yellow LED
Outdoor
Keeps flashing
5. Troubleshooting
service valve fully
connections of indoor
heat exchanger and/or return air
temperature thermistor
characteristics of indoor heat
exchanger and/or return air
temperature thermistor
pressure during operation
Indoor heat exchanger, return air temperature thermistor
Temperature-resistance characteristics
(Broken wire)
(Short circuit)
TIMER light
Content
ON
Insufficient refrigerant amount
Red LED
or detection of service valve closure
1 time flash
Diagnosis
Is the
opened?
YES
Are the
connectors OK?
YES
Are the
OK?
YES
Is the low
normal?
15
10
5kΩ at 25°C
5
0 10 20 30 40 50
Temperature (°C)
450
- -
'12 • PAC-T-174
Countermeasure
Open fully.
NO
Correct indoor heat
NO
exchanger, return air
temperature thermistor
connector connections.
Defective indoor heat
NO
exchanger, return air
temperature thermistor ➞
Replace.
Charge refrigerant.
NO
Defective indoor control
YES
PCB ➞ Replace. (Defective
indoor heat exchanger,
return air temperature
thermistor input circuits)