Mitsubishi Electric PUHZ-SHW80VHA Service Manual page 49

S y mp toms: N oth ing is disp lay ed on th e remote c ontroller. 1
Diagnosis flow
Check the voltage between S1
and S2 on the terminal block
(TB 4) of the indoor unit which
is used to connect the indoor
unit and the outdoor unit.
19 8 to 264 V AC?
Y ES
Check the voltage of indoor
controller board (CN2D).
12 V to 16 V DC?
NO
Check the voltage of the unit after
removing the indoor power board
(CN2S).
12 V to 16 V DC?
NO
OCH526C
NO
Check the voltage among L(L ) and
3
N on the terminal block (TB 1) of the
outdoor power circuit board.
19 8 to 264 V AC?
Y ES
Check the voltage between S1
and S2 on the terminal block
(TB 1) of the outdoor unit which
is used to connect the indoor
unit and the outdoor unit.
19 8 to 264 V AC?
Y ES
Y ES
Y ES
Cause
NO
Troubles concerning
power supply
NO
outdoor controller
board
outdoor controller
circuit board are
blown.
outdoor controller
board
outdoor controller
circuit board are
blown.
controller board
or poor connection of
in door/ outdoor
connecting wire
power board
LED display of the indoor
controller board
LED1 :
LED2 :
LED3 :
Inspection method and
troubleshooting
to the outdoor unit.
outdoor unit.
Check if the fuses are blown.
The fuses on the outdoor
controller circuit board will
be blown when the indoor
/ outdoor connecting wire
short-circuits.
or poor contact is causing this
problem. Indoor/ outdoor
connecting wire is polarized
3-core type. Connect the
indoor unit and the outdoor
unit by wiring each pair of
side of indoor/ outdoor
terminal blocks.
controller board.
Check if there is miswiring
or breaking of wire.
power board.