Mitsubishi Heavy Industries FDT28KXE6A Service Manual page 95

Error code
E53/E55*1
Remote controller:
E53/E55-1, 2
7-segment display:
*1 E55-1 : Tho-C1, E55-2: Tho-C2 *2 E53 : E53·E55-1 time flash, E55-2: 2 time flash
1. Applicable model
Outdoor unit
2. Error detection method
Detection of anomalously low
temperature (resistance) of
Tho-S or Tho-C1, C2
3. Condition of error displayed
• if -50°C or lower is detected
for 5 seconds continuously
within 2 minutes to 2 minutes
20 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 *2
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?
*2
*2 Check several times to prove any poor connection
Temperature-resistance characreristics of
suction pipe temperature thermistor (Tho-S)
5kΩ at 25 (ºC)
Temperature (ºC)
93
–
Content
Suction pipe temperature thermistor anomaly (Tho-S),
Under-dome temperature thermistor anomaly (Tho-C1, C2)
Regarding the characteristics of
the thermistor, see the following chart
Temperature-resistance characreristics of
under-dome temperature thermistor (Tho-C1, C2)
200
180
160
140
120
100
80
60
40
20
0
0 20
–
Countermeasure
Check and save the data of
operating conditions
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
NO
securely
Replace thermistor
NO
(Tho-S or Tho-C1, C2)
Replace outdoor control
YES
PCB
40 60 80 100 120 140
Temperature (ºC)
160