Power Transistor Temperature Thermistor Anomaly (Tho-P1) - Mitsubishi Heavy Industries Hi-COP Series Service Manual

Error code
E56
Remote control:
E56-1
7-segment display:
1. Applicable model
Outdoor unit
2. Error detection method
Detection of anomalously low
temperature (resistance) of
Tho-P1.
3. Condition of error displayed
When the outdoor air temperature
is above 0ºC, if -10ºC or lower
is detected for 20 seconds
continuously within 10 minutes
to 10 minutes 30 seconds after
compressor ON, compressor stops.
When the compressor is restarted
automatically after 3-minutes
delay, if this anomaly occurs 3
times within 40 minutes.
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 OK
?
YES
Note ( 1 )
(1)
Are the
characteristics of
thermistor OK?
※1
※1Check several times to prove any poor connection.
Temperature-resistance characteristics of power transistor
temperature thermisor (Tho-P1)
200
180
160
140
120
100
80
60
40
20
0
0 20 40
Temperature (°C)
120
–
Content
Power transistor temperature
thermistor anomaly (Tho-P1)
NO
Regarding the characteristics of
the thermistor, see the following.
NO
YES
60 80 100 120 140
–
'14 • KX-SM-204
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
of Mente PC data with
actual measured value.
Insert the connector
securely.
Replace power transistor
temperature thermistor
(Tho-P1).
Replace outdoor control
PCB.