Mitsubishi Electric PKA-A24KA8 Service Manual page 18

9-4. TROUBLESHOOTING OF PROBLEMS
Phenomena
(1)LED2 on indoor controller board
is off.
(2)LED2 on indoor controller board
is blinking.
TCH115A
Note: Refer to the outdoor unit's service manual for the detail of remote controller.
Cause
• When LED1 on indoor controller board is also off.
Power supply of rated voltage is not supplied to out-
door unit.
Defective outdoor controller circuit board
Power supply of 208/230 V is not supplied to indoor
unit.
Defective indoor controller board
• When LED1 on indoor controller board is lit.
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.
Miswiring of remote controller wires
Under twin or triple indoor unit system, 2 or more
indoor units are wired together.
Refrigerant address for outdoor unit is wrong or not
set.
Under grouping control system, there are some units
whose refrigerant addresses are 0.
Short-circuit of remote controller wires
Defective remote controller
Check the voltage of outdoor power
supply terminal block (L1, L2).
• When 208/230 V AC is not detected,
check the power wiring to outdoor unit
and the breaker.
• When 208/230 V AC is detected, check
Check the voltage between outdoor
terminal block S1 and S2.
• When 208/230 V AC is not detected,
—check the fuse on outdoor controller
circuit board.
—check the wiring connection.
• When 208/230 V AC is detected, check
Check the voltage between indoor termi-
nal block S1 and S2.
• When 208/230 V AC is not detected,
check indoor/outdoor unit connecting
wire for miswiring.
• When 208/230 V AC is detected,
check
Check the fuse on indoor controller board.
Check the wiring connection.
If no problem is found, indoor controller
board is defective.
Check again 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.
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.
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-
circuit 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.
18
Countermeasure
(below).
(below).
(below).