Mitsubishi Heavy Industries SRC25QA-S, Technical Manual, Page: 53 / 102

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Error of outdoor unit (Damage of power transistor, wiring break of compressor)
Compressor over heat (Insufficient refrigerant, failure of discharge pipe sensor)
Power cut (Open-phase of output terminal of compressor, compressor lock)
Failure of inverter
No
No
Yes
Yes
Conne
ct it
proper
ly.
Check the compressor.
No
Yes
Yes
Yes
Yes
Yes
Has
the
wiring
for the
compr
essor
been
proper
ly
conne
cted?
Has
all
three-
phase
output
voltag
e been
applie
d to
the
power
transis
tor?
(For
details
, see
P49.)
Whether there is no short circuit?
Check the compressor.
Visually inspect wiring of
compressor
Check insulating resistor (above 1M
Ω
)
Check winding coil resistor (about several
Ω
)
In normal cases, the compressor is locked.
Ensure the space of air suction and air
blowing.
Has all three-phase output voltage been applied
to the power transistor?
Disconnect the wiring of
the compressor and
operate the inverter to
check whether the power
cut function does not
work.
No No
Is the resistance value of the
discharge pipe sensor normal?
(For details, see P43.)
Check that the connection of the connector is
correct; check the resistance value; replace
the discharge pipe sensor.
Yes
Is the refrigerant circulating load
normal?
Is the situation the same after
refrigerant is charged?
Insufficient
refrigerant
Failure of inverter Blockage of hush pipe, etc.
No
No
No
Failure of inverter
Failure of inverter