Mitsubishi Heavy Industries FDT28KXE6A Service Manual page 71

Error code
E7
Remote controller:
-
7-segment display:
1. Applicable model
All models
2. Error detection method
Detection of anomalously low
temperature (resistance) of
Thi-A
3. Condition of error displayed
• If -50°C or lower is
detected for 5 seconds
continuously, compressor
stops. After 3-minutes delay
the compressor is restarted
automatically, but if this
anomaly occurs again within
60 minutes after the initial
detection.
• Or if 48°C or higher is
detected for 5 seconds
continuously.
4. Presumable cause
• Anomalous connection of
indoor return air temperature
thermistor
• Indoor return air temperature
thermistor anomaly
• Indoor control PCB anomaly
Note:
LED Green Red
Keeps flashing 1 time flash
Indoor
Keeps flashing Stays Off
Outdoor
5. Troubleshooting
Diagnosis
Is
the connector of
thermistor connected
properly ?
YES
Are
the characteristics
of thermistor OK?
*1
*1 Check several times to prove any poor connection
Temperature-resistance characreristics of indoor
return air temperature thermistor (Thi-A)
15
10
5
0 10
Temperature (°C)
69
–
Indoor return air
Content
temperature thermistor anomaly (Thi-A)
NO
Regarding the characteristics of
the thermistor, see the following chart
NO
YES
°C
5kΩ at 25
20 30 40 50
–
Countermeasure
Insert the connector
securely
Replace thermistor
(Thi-A)
Replace indoor control
PCB