Mitsubishi Electric FDT125VNVF Technical Manual page 446

Indoor display
Error code
E49
Remote controller:
inverter PCB
1. Applicable model
All models
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.
RUN light
–
Green LED
Outdoor
control PCB
Keeps flashing
Yellow LED
Outdoor
Keeps flashing
5. Troubleshooting
Check the low pressure value during
following state from the remote controller
� Compressor is stopping
� Compressor is operating
NO
Check the insulation resistance of pressure sensor.
insulation resistance more than 100Ω
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.
To checking of refrigerant
amount, refrigerant circuit,
etc.
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TIMER light
Content
–
Red LED
1 time flash
low pressure sensor anomaly (1/2)
Diagnosis
Is the low
pressure sensor connection OK
(at PCB side)?
YES
During
both � and � state low
pressure detected at around 0MPa
without any
fluctuation.
YES
Is the
at DC500V?
YES
*
Is the
pressure difference less than
0.2MPa?
Connect the pressure sensor of
YES
spare part to outdoor control
PCB in the condition open to
atmosphere.
Is the pressure
0MPa displayed on the remote
controller?
445
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'12 • PAC-T-174
Low pressure error or
Countermeasure
Correct.
NO
Replace low pressure
NO
sensor.
NO
Defective outdoor control
NO
PCB ➞ Replace.
Replace low pressure
YES
sensor.