Mitsubishi Heavy Industries SCM71ZM-S1 Technical Manual page 278

Error code
E53
Remote control:
1. Applicable model
All models
2. Error detection method
Detection of anomalously low
temperature (resistance) on
suction pipe temperature sensor
3. Condition of error displayed
• When the temperature sensor
detects -55 °C or lower for 5
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 within 20 second
after power ON.
4. Presumable cause
• Defective outdoor sub PCB
• Broken sensor harness or
temperature sensing section
(Check molding.)
• Disconnected wire connection
(connector)
Note:
LED Green Red
Keeps flashing Stays OFF
Indoor
– 8-time flash
Outdoor
5. Troubleshooting
Diagnosis
Is
the suction pipe
temperature sensor connector
connected properly?
YES
Is the
characteristics of the
suction pipe temperature
sensor
OK?
Temperature-resistance characteristics
(Broken wire)
15
10
5
(Short circuit)
0 10 20
Temperature (°C)
277
-
Content
Suction pipe temperature
sensor anomaly
NO
For the characteristics of suction pipe
temperature sensor, see the following graph.
NO
YES
5kΩ at 25°C
30 40 50
-
'17 • SCM-T-225
Countermeasure
Correct connector.
Defective suction pipe
temperature sensor ➞
Replace.
Defective outdoor sub
PCB ➞ Replace.
(Defective suction pipe
temperature sensor input
circuit)