Troubleshooting By Inferior Phenomena - Mitsubishi Electric Mr.SLIM SLZ-KA25VA 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 rated voltage is not supplied to out-
door unit.
2 Defective outdoor controller circuit board
3 Power supply of 220~240V is not supplied to indoor
unit.
4 Defective indoor power board
5 Defective indoor controller board
• When LED1 on indoor controller board is lit.
1 Mis-setting of refrigerant address for outdoor unit
(There is no unit corresponding to refrigerant
address "0".)
• 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
Under twin indoor unit system, 2 or more indoor units
2 Refrigerant address for outdoor unit is wrong or not
set.
Under grouping control system, there are some units
whose refrigerant address is 0.
3 Short-cut of remote controller wires
4 Defective remote controller
Note: Refer to the manual of outdoor unit for the detail of remote
controller.
1 Check the voltage of outdoor power
supply terminal block (L, N) or (L
• When AC 220~240V is not detected,
check the power wiring to outdoor unit
and the breaker.
• When AC 220~240V is detected,
check 2 (below).
2 Check the voltage between outdoor
terminal block S1 and S2.
• When AC 220~240V is not detected,
—check the fuse on outdoor controller
circuit board.
—check the wiring connection.
• When AC 220~240V is detected,
check 3 (below).
3 Check the voltage between indoor terminal
block S1 and S2.
• When AC 220~240V is not detected,
check indoor/outdoor unit connecting
wire for miswiring.
• When AC 220~240V is detected,
check 4 (below).
4 Check voltage output from CN2S on indoor
power board (DC13.1V). Refer to 7-5.
• When no voltage is output,
check the wiring connection.
• When output voltage is between
DC12.5V and DC13.7V,
check 5 (below).
5 Check the wiring connection between
indoor controller board and indoor power
board. Check the fuse on indoor controller
board. If no problems are found, indoor
controller board is defective.
1 Check the setting of refrigerant address
for outdoor unit.
Set the refrigerant address to "0".
(For grouping control system under
which 2 or more outdoor units are
connected, set one of the units to "0".)
Set refrigerant address using SW1 (3-6)
on outdoor controller circuit board.
Check indoor/outdoor unit connecting wire
for connection failure.
1 Check the connection of remote cotroller
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 Check the setting of refrigerant address
in case of grouping control system. If
there are some units whose refrigerant
addresses are 0 in one group, set one of
the units to 0 using SW1 (3-6) on out-
door controller circuit board.
34 Remove remote controller wires and
check LED2 on indoor controller board.
• 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.
20
Countermeasure
, N).
3