E7 Return Air Temperature Sensor Anomaly - Mitsubishi Heavy Industries FDT40ZSXW1VH Service Manual

Error code
Remote control: E7
1. Applicable model
All models
2. Error detection method
Anomalously low temperature
or high temperature (resistance)
is detected by indoor return air
temperature sensor (Thi-A)
3. Condition of error displayed
• When the temperature sensor
detects -50°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 sensor connector
• Defective return air
temperature sensor
• Faulty indoor unit control
PCB
Note:
LED Green Red
Keeps flashing 1-time flash
Indoor
5. Troubleshooting
Diagnosis
Is the
connection of return
air temperature sensor
connector OK?
YES
Are the
characteristics of return air
temperature sensor
OK?
Temperature-resistance characteristic
(Broken wire)
15
10
5
(Short-circuit)
0
64
-
Content
Return air temperature
sensor anomaly
NO
NO
YES
°C
5kΩ at 25
10 20 30 40 50
Temperature (°C)
-
'19 • PAC-SM-302
Countermeasure
Correct. ➞ Connect
connector.
Defective return air
temperature sensor ➞
Replace.
Defective indoor unit
control PCB ➞ Replace.
(Defective return air
temperature sensor input
circuit)