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P-MX4HPM-06E1
Troubleshooting by Indication on the Remote Control
3.34 “L8” Outdoor Unit: Inverter Current Abnormal
Remote Control
Display
L8
Applicable
Models
U-5MX4XPQ ~ U-54MX4XPQ
Method of
Malfunction
Detection
Malfunction is detected by current flowing in the power transistor.
Malfunction
Decision
Conditions
When overload in the compressor is detected. (Inverter secondary current 16.1A)
Supposed
Causes
Troubleshooting
Output current check
Compressor overload
Compressor coil disconnected
Defect of inverter PC board
Faulty compressor
Be sure to turn off power switch before connect or disconnect connector,
Caution or parts damage may be occurred.
Power ON
A current
of not less than 15A flows
through the compressor.
YES
NO
Is the stop valve open?
NO
Overcurrent:
Check the compressor
and refrigerant system
(in the same manner as
that for E3).
Open the stop valve.
YES
Are wire
connections properly
made (according to the
Wiring Diagram)?
NO
Check the compressor cable for
any disconnection or flaws.
YES
Rectify the wire
connetions.
Disconnect the cable from the
compressor, and then check the
compressor for the insulation
resistance.
Power OFF
NO
The insulation
resistance is low, i.e.,
not more than
100kΩ.)
YES
Replace the
compressor.
NO
Check the power transistor on
the inverter PC board using a
multiple tester.
NO
Does the
power transistor have any
abnormalities?
NO
Connect the compressor cable,
and then restart the operation.
A
Troubleshooting
YES
Replace the inverter
PCB.
The inverter is likely to
have got faulty due to
the malfunction of the
compressor.
After the completion of
replacement, be sure
to check the
compresssor.
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