Troubleshooting By Inferior Phenomena - Mitsubishi Electric Mr.SLIM PC-2GAKD Technical & Service Manual

7-4. TROUBLESHOOTING BY INFERIOR PHENOMENA

Phenomena
(1)LED2 on indoor controller board
is off.
(2)LED2 on indoor controller board
is blinking.
Cause
• When LED1 on indoor controller board is also off.
1 Power supply of 220~240V AC is not supplied to
indoor unit.
2 Defective indoor controller board
3 Defective indoor power board
• When LED1 on indoor controller board is lit.
1 Mis-setting of main/sub for indoor unit
(There is no unit corresponding to main unit.)
• When LED1 on indoor controller board is also blinking.
Connection failure of indoor/outdoor unit connecting
wire
• When LED1 is lit.
1 Miswiring of remote controller wires
When 2 indoor units are wired in one refrigerant
system, each indoor unit sets as main unit. (SW5-3)
2 Short-cut of indoor/outdoor unit connecting wire
3 Short-cut of remote controller wires
4 Defective remote controller
1 Check the voltage of indoor power supply
terminal block (L,N).
• When AC220~240V is not detected,
check the power supply wiring.
• When AC220~240V is detected,
check 2 (below).
2 Check voltage output from CNDK on
indoor controller board.
• When AC220~240V is not detected,
check the fuse on indoor controller
board.
Check the wiring connection between
indoor power supply terminal block, and
CND on indoor controller board.
• When AC220~240V is detected,
check 3 (below).
3 Check voltage output from CN2S on
indoor power board.
• When no voltage output.
check the wiring connection between
CNDK on indoor controller board and
CNSK on indoor power board.
If no problem are found, indoor power
board is defective.
• When DC12.5~13.7V is detected,
check the wiring connection between
CN2S on indoor power board and
CN2D on indoor power board.
If no problem are found, indoor con-
troller board is defective.
1 Check the setting of main/sub for indoor
unit.
Set the main unit.
Set main/sub using SW5-3 on indoor
controller board.
Check indoor/outdoor unit connecting wire
for connection failure.
1 Check the connection of remote con-
troller wires in case of twin triple indoor
unit system. When 2 or more indoor units
are wired in one refrigerant system,
connect remote controller wires to one of
those units.
2 Remove indoor/outdoor connecting wires
and check LED2 on indoor controller
board.
• When LED2 is blinking, check the short-
cut of indoor/outdoor connecting wires.
• When LED2 is lit, connect indoor/outdoor
connecting wires again, and; if LED2 is
blinking, outdoor unit's controller board is
defective; if LED2 is lit, connection failure
of indoor/outdoor terminal block etc. has
returned to normal.
34 Remove remote controller wires and
• When LED2 is blinking, check the
short-cut of remote controller wires.
• When LED2 is lit, connect remote
controller wires again and:
if LED2 is blinking, remote controller
is defective; if LED2 is lit, connection
failure of remote controller terminal
block etc. has returned to normal.
32
Countermeasure
check LED2 on indoor controller board.