Discharge Pipe Temperature Thermistor Anomaly - Mitsubishi Heavy Industries FDT Series Technical Manual

Error code
Indoor control PCB
E39
Remote controller:
Outdoor control PCB
Outdoor inverter
Note (1) Value in is for the models SRC40-60.
1. Applicable model
All models
2. Error detection method
Detection of anomalously low
temperature (resistance) on
the discharge pipe temperature
thermistor
3. Condition of Error displayed
When the temperature thermistor
detects -10(-25)°C or lower for
5 seconds continuously within
10 minutes to 10 minutes 20
seconds after the compressor
ON, the compressor stops. After
3-minutes delay, the compressor
starts again automatically, but
if this anomalous temperature
is detected 3 times within 40
minutes.
Note (1) Value in ( ) is for the models
SRC40-60.
4. Presumable cause
• Defective outdoor control
PCB
• Broken thermistor harness or
temperature sensing section
(Check molding.)
• Disconnected wire connection
(connector)
Note:
LED Green
Keeps flashing
Keeps flashing
Yellow
PCB
Keeps flashing
5. Troubleshooting
Is the
discharge pipe
temperature thermistor
connector connected
properly?
YES
Are the
characteristics
of discharge pipe
temperature
thermistor
OK?
• Models SRC40-60
(Broken wire) Temperature-resistance characteristics
100
50
0
[T 90 ]
°C
0 20
(Short circuit)
• Models FDC71-140
Temperature-resistance characteristics
(Broken wire)
200
100
180
160
T?80?
T?80?
140
120
100
50
80
60
(k)
40
20
0
0
0 20
0
(Short circuit)
Red
Content
Stays OFF
Discharge pipe temperature
1 8 time flash
thermistor anomaly
Diagnosis
NO
For the characteristics of discharge pipe
temperature thermistor, see the following graph.
NO
YES
40 60 80 100 120
Temperature (°C)
10
T?80?
5
0
40 60 80 100 120 140
50 80 100
Temperature (°C)
?
- 402 -
'12 • PAC-T-173
Countermeasure
Correct connector.
Defective discharge pipe
temperature thermistor
Replace.
Defective outdoor control
PCB Replace.
(Defective temperature
thermistor input circuit)
140
T?80?
(k)
160