Mitsubishi Electric Mr. SLIM SLZ-M15FA2.TH Technical & Service Manual page 24

9-4. TROUBLESHOOTING OF PROBLEMS
Phenomena
(1) LED2 on indoor controller board
is off.
(2) LED2 on indoor controller board
is blinking.
TCH067A
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
Power supply of 220–240 V AC is not supplied to
indoor unit.
4 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.
Short-cut of remote controller wires
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 220–240 V AC is not detected,
check the power wiring to outdoor unit
and the breaker.
• When 220–240 V AC is detected,
check 2 (below).
2 Check the voltage between outdoor
terminal block S1 and S2.
• When 220–240 V AC is not detected,
—check the fuse on outdoor controller
circuit board.
—check the wiring connection.
• When 220–240 V AC is detected,
check
Check the voltage between indoor terminal
block S1 and S2.
• When 220–240 V AC is not detected,
check indoor/outdoor unit connecting
wire for miswiring.
• When 220–240 V AC is detected,
check
4 Check the wiring connection between
TB4 and CN01. 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
controller 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 outdoor
controller circuit board.
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.
24
Countermeasure
, N).
3
(below).
(below).