Low Pressure Error Or Low Pressure Sensor Anomaly - Mitsubishi Heavy Industries FDTC50ZHXV Technical Manual

Error code
Remote controller: E49
1. Applicable model
Model FDC 71 – 250
2. Error detection method
Detected by low pressure drop
and suction superheat
3. Condition of Error displayed
➀ When the low pressure sensor
detects 0.079MPa or lower
for 15 seconds continuously,
compressor stops and it
restarts automatically after
3-minutes delay. And if
this anomaly occurs 3 times
within 60 minutes,
➁ 10 minutes after the
compressor starts, if the
low pressure sensor detects
0.15MPa or lower for 60
minutes continuously and
compressor suction superheat
is detected 30degC or higher
for 60 minutes continuously.
And if this anomaly occurs 3
times within 60 minutes,
➂ If low pressure sensor
detects 0.079MPa or lower
for 5 minutes continuously
(including the compressor
stop status),
4. Presumable cause
• Defective outdoor control
PCB
• Defective low pressure sensor
connector
• Defective low pressure sensor
• Defective suction pipe
temperature thermistor
connector
• Defective suction pipe
temperature thermistor
Note:
* Connect the gauge manifold to the service valve check joint during cooling, or connect it to the check joint at internal
piping of outdoor unit during heating.
LED Green Red
Keeps flashing Stays Off
Indoor
Keeps flashing 1 time flash
Outdoor
5. Troubleshooting
Diagnosis
Is the low
pressure sensor connection OK
(at PCB side)?
Check the low pressure value during
following state from the remote controller
� Compressor is stopping
� Compressor is operating
both � and � state low
pressure detected at around 0MPa
NO
without any
fluctuation.
Check the insulation resistance of pressure sensor.
insulation resistance more than 100Ω?
at DC500V?
After connecting the gauge manifold on the low pressure
line, measure at the state � above. Compare the result
with the value indicated on the remote controller.
pressure difference less than
0.2MPa?
YES
To checking of refrigerant
amount, refrigerant circuit,
etc. (next page)
0MPa displayed on the remote
313
–
Low pressure error or
Content
low pressure sensor anomaly (1/2)
(Model FDC71 - 250)
NO
YES
During
YES
Is the
NO
YES
*
Is the
NO
Connect the pressure sensor of
spare part to outdoor control
PCB in the condition open to
atmosphere.
Is the pressure
controller?
YES
–
Countermeasure
Correct.
Replace low pressure
sensor.
Replace outdoor control
NO
PCB.
Replace low pressure
sensor.