Mitsubishi Electric FDT125VNVF Technical Manual page 404

Error code
Indoor control PCB
E53
Remote controller:
Outdoor control PCB
Outdoor inverter
1. Applicable model
All models
2. Error detection method
When the suction pipe
temperature thermistor detects
anomalously low temperature
3. Condition of Error displayed
If the temperature thermistor
detects -50°C or lower for 5
seconds continuously within
10 minutes to 10 minutes 20
seconds after compressor ON,
the compressor stops. When
the compressor is restarted
automatically after 3-minutes
delay, if this anomaly ocuurs 3
times within 40 minute.
4. Presumable cause
• Defective suction pipe
temperature thermistor
connection
• Defective suction pipe
temperature thermistor
• Defective outdoor control
PCB
Note:
LED Green
Keeps flashing
Keeps flashing
Yellow LED or Red LED Green LED
PCB
Keeps flashing
5. Troubleshooting
Is the connection
of suction pipe temperature thermistor
connector OK?
characteristics of suction pipe
temperature thermistor OK?
Temperature-resistance characteristics
(Broken wire)
15
10
5
(Short circuit)
Red
Content
Stays OFF
Suction pipe temperature
1 time flash
thermistor anomaly
Keeps flashing
Diagnosis
YES
Are the
YES
5kΩ at 25°C
0 10 20 30 40 50
Temperature (°C)
403
- -
'12 • PAC-T-174
Countermeasure
Correct connection of
NO
suction pipe temperature
thermistor connector.
Defective suction pipe
NO
temperature thermistor ➞
Replace.
Defective outdoor control
PCB ➞ Replace.
(Defective suction pipe
temperature thermistor
input circuit)