Return Air Temperature Thermistor Anomaly - Mitsubishi Electric FDT125VNVF Technical Manual

Error code
E7
Remote controller:
1. Applicable model
All models
2. Error detection method
Anomalously low temperature
or high temperature (resistance)
is detected by indoor return air
temperature thermistor (ThI-A)
3. Condition of Error displayed
• When the temperature thermistor
detects -20°C or lower for
5 seconds continuously, the
compressor stops. After 3-minute
delay, the compressor starts again
automatically, but if this error
occurs again within 60 minutes
after the initial detection.
4. Presumable cause
• Defective return air
temperature thermistor
connector
• Defective return air
temperature thermistor
• Faulty indoor control PCB
Note:
LED Green Red
Keeps flashing 1 time flash
Indoor
Keeps flashing Stays OFF
Outdoor
5. Troubleshooting
Diagnosis
Is the
connection of return
air temperature thermistor
connector OK?
YES
Are the
characteristics of return air
temperature thermistor
OK?
Temperature-resistance characteristic
(Broken wire)
15
10
5
(Short circuit)
0
377
-
Content
Return air temperature
thermistor anomaly
NO
NO
YES
°C
5kΩ at 25
10 20 30 40 50
Temperature (°C)
-
'12 • PAC-T-174
Countermeasure
Correct. ➞ Connect
connector.
Defective return air
temperature thermistor ➞
Replace.
Defective indoor control
PCB ➞ Replace.
(Defective return air
temperature thermistor
input circuit)