Outdoor Heat Exchanger Temperature Sensor Anomaly - Mitsubishi Heavy Industries FDTC40ZSXVH Service Manual

Error code
E37
Remote control:
1. Applicable model
All models
2. Error detection method
Detection of anomalously low
temperature (resistance) on
the outdoor heat exchanger
temperature sensor
3. Condition of error displayed
• When the temperature sensor
detects-55°C or lower for 20
seconds continuously within 2
minutes to 2 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.
• When -55°C or lower is detected for 5
seconds continuously within 20 seconds
after compressor ON.
4. Presumable cause
• Defective outdoor unit control
PCB
• Broken sensor harness or
temperature sensing section
• Disconnected wire connection
(connector)
Note:
LED Green Red
Keeps flashing Stays OFF
Indoor
- 8-time flash
Outdoor
5. Troubleshooting
Diagnosis
Is the
outdoor heat
exchanger temperature
sensor connector
connected
properly?
YES
For the characteristics of outdoor heat exchanger
temperature sensor, see the following graph.
Are the
characteristics of
outdoor heat exchanger
temperature
sensor
OK?
Temperature-resistance characteristics
(Broken wire)
15
10
5
(Short-circuit)
0
76
-
Content
Outdoor heat exchanger
temperature sensor anomaly
NO
NO
YES
5kΩ at 25°C
10 20 30 40 50
Temperature (°C)
-
'18 • PAC-SM-297
Countermeasure
Correct connector.
Defective outdoor heat
exchanger temperature
sensor ➞ Replace.
Defective outdoor unit
PCB ➞ Replace.
(Defective outdoor heat
exchanger temperature
sensor input circuit)