Mitsubishi Heavy Industries FDT71VNXVD Service Manual page 84

Error code
Remote controller: E49
1. Applicable model
All models
2. Error detection method
Detected by low pressure drop
and suction superheat
3. Condition of Error displayed
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,
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,
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
Content
Indoor Keeps flashing Stays OFF
Outdoor 1 time flash
Keeps flashing
5. Troubleshooting
Diagnosis
Is the low
pressure sensor connection OK
(at PCB side)?
YES
Check the low pressure value during
following state from the remote controller
Compressor is stopping
Compressor is operating
During
both and
NO pressure detected at around 0MPa
without any
fluctuation.
YES
Check the insulation resistance of pressure sensor.
Is the
insulation resistance more than 100 ?
at DC500V?
YES
After connecting the gauge manifold on the low pressure
line, measure at the state
with the value indicated on the remote controller.
Is the
pressure difference less than
0.2MPa?
YES
To checking of refrigerant
amount, refrigerant circuit,
etc. (next page)
0MPa displayed on the remote
84 94
– –
Low pressure error or
low pressure sensor anomaly (1/2)
NO
state low
NO
*
above. Compare the result
NO
Connect the pressure sensor of
spare part to outdoor control
PCB in the condition open to
atmosphere.
Is the pressure
NO
controller?
YES
'10 • PAC-SM-137A
Countermeasure
Correct.
Replace low pressure
sensor.
Defective outdoor control
PCB Replace.
Replace low pressure
sensor.