Midea MSY-09HRDN1-QC8 Service Manual page 41

Is all connections on PCB
and between PCB and
compressor good?
Replace the outdoor
PCB and then repower
on. Is the failure
cleared?
9.2.8 P1(over voltage or too low voltage protection) diagnosis and solution.
Is the power supply
good?
9.2.9 P2(temperature protection of compressor top) diagnosis and solution.
Does
compressor
YES
Is refrigerant
circulation
volume
normal?
NO
Charge
refrigerant
Is abnormality
the same after
gas charging?
NO
9.2.10 P4(inverter compressor drive error) diagnosis and solution.
YES
YES
NO
Check the
outdoor main
PCB. Is there some
problem?
NO
NO
NO
Is the
connection
good?
YES
Is protector
normal?
YES
YES
Repair or correct the
connector or connection.
Check the compressor
Be sure the power supply
is normal when using the
units
Replace the outdoor
e-box.
NO
Reconnect and retest.
NO
Replace the protector.
Replace the outdoor
PCB.
Check refrigerant system
(such as clogging of
capillary, etc)
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