Outdoor Air Temperature Thermistor Anomaly (Tho-A) - Mitsubishi Heavy Industries KXZ Series Service Manual

Error code
E38
Remote control:
E38
7-segment display: –
1. Applicable model
Outdoor unit
2. Error detection method
Detection of anomalously low
temperature (resistance) of
Tho-A
3. Condition of error displayed
• If -30°C or lower is detected for 5 seconds
continuously within 2-minutes to 2-minutes
20-seconds after the compressor ON, the
compressor stops. And after 3-minutes delay,
the compressor starts again automatically, but if
this anomalous temperature is detected 3 times
within 40 minutes after the initial detection.
• If -30°C or lower is detected for 5 seconds
continuously within 20 seconds after power ON.
4. Presumable cause
• Broken thermistor harness or
the internal wire of sensing
section (Check the molded
section as well)
• Disconnection of thermistor
harness connection (connector).
• Outdoor control PCB anomaly.
Note:
LED Green Red
Keeps flashing Stays OFF
Indoor
Keeps flashing 1-time flash
Outdoor
5. Troubleshooting
Diagnosis
Save data for 30 minutes before stopping in Mente PC.
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 characteristics of
outdoor air temperature thermistor (Tho-A)
100
90
80
70
60
50
40
30
20
10
0
-20 -10
Temperature (°C)
98
-
Outdoor air temperature
Content
thermistor anomaly (Tho-A)
NO
NO
YES
0 10 20
30 40 50
-
'14 • KX-SM-221
Countermeasure
Check and save the data of
operating condition.
Check the conditions whether
it occurs immediately after the
power on or during operation
or stopping.
Check the sensed value.
Compare the temperature
on Mente PC with actual
measured value.
Insert the connector
securely.
Replace thermistor
(Tho-A).
Replace outdoor control
PCB.