Mitsubishi Electric PCA-A24GA Service Manual page 20

Phenomena
(1)LED2 on indoor controller board
is off.
(2)LED2 on indoor controller board
is blinking.
(3)Upward/downward vane
performance failure
(4)Receiver for wireless remote
controller
Note: Refer to the manual of the outdoor unit for the detail of remote controller.
Cause
• 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 indoor unit system, 2 indoor units are wired
together.
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 Shortcut of remote controller wires
4 Defective remote controller
1 The vane is not downward during defrosting and
heat preparation and when the thermostat is OFF in
HEAT mode. (Working of COOL protection function)
2 Vane motor does not rotate.
• Defective vane motor
• Breaking of wire or connection failure of connector
• Up/down vane setting is "No vanes".
3 Upward/downward vane does not work.
• The vane is set to fixed position.
1 Weak batteries of wireless remote controller
2 Contact failure of connector (CNB) on wireless
remote controller board(Insert failure)
3 Contact failure of connector (CN90) on indoor con-
troller board(Insert failure)
4 Contact failure of connector between wireless
remote controller board and indoor controller board
1 Reconfirm 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 con-
troller wires in case of twin 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.
34 Remove remote controller wires and
check LED2 on indoor controller board.
• When LED2 is blinking, check the
shortcut 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.
1 Normal operation (The vane is set to hor-
izontal regardless of remote control.)
2 Check 2 (left).
• Check the vane motor. (Refer to "How
to check the parts".)
• Check for breaking of wire or connec-
tion failure of connector.
• Check "Up/down vane setting". (Unit
function selection by remote controller).
3 Normal operation (Each connector on
vane motor side is disconnected.)
1 Replace batteries of the wireless remote
controller.
2~4
Check contact failure of each connector.
If no problems are found in connector,
replace indoor controller board.
When the same trouble occurs even if
indoor controller board is replaced,
replace wireless remote controller
board.
20
Countermeasure