Mitsubishi Electric PUHZ-SHW80VHA Service Manual page 50

S y mp toms: N oth ing is disp lay ed on th e remote c ontroller. 2
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 status
of the indoor controller
board LED3 display.
B linking.
Check the refrigerant address of
the outdoor unit. (SW1-3 to 1-6)
Is the refrigerant
address "0"?
Y ES
Check the LED display of the
outdoor unit after turning on the
main power again.
Is anything displayed?
Displayed.
Is "EA" or "Eb"
displayed?
Y ES
Check the voltage between S2
and S3 on the terminal block of
the outdoor unit.
17 to 28 V DC?
Y ES
OCH526C
NO
Not lighting.
Check the looseness or disconnection
of the indoor/ outdoor connecting wire.
Are there looseness or
disconnection of the indoor/
outdoor connecting wire?
NO
NO
Not displayed.
NO
Is "E8" displayed?
NO
Can the unit be restarted?
Can all the indoor
unit be operated?
Y ES
NO
Cause
Y ES
contact of the indoor/
outdoor connecting
wire
Only the unit which
has the refrigerant
address "0" supplies
power to the remote
controller
controller circuit
board
Y ES
controller circuit
board
NO
controller board
electromagnetic
noise
power circuit board
power board
LED display of the indoor
controller board
LED1 :
LED2 :
LED3 : or
Inspection method and
troubleshooting
contact of the indoor/ outdoor
connecting wire.
address to "0". In case of
the multiple grouping
system, recheck the
refrigerant address again.
controller circuit board.
controller circuit board.
board of the indoor unit which
does not operate.
There may be the influence
of electromagnetic noise.
Check the transmission wire
and get rid of the causes.
power circuit board.
power board.