Mitsubishi Electric Mr. SLIM PKA Series Service Manual page 24

Phenomena
(2) LED2 on indoor controller board
is blinking.
(3) Upward/downward vane perform-
ance failure
(4) Receiver for wireless remote
controller
TCH069A
Note: Refer to the outdoor unit's service manual for the detail of remote controller.
Cause
• 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 triple indoor unit system, 2 or more 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 addresses are 0.
3 Short-circuit 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
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
Check indoor/outdoor unit connecting wire
for connection failure.
1 Check the connection of remote controller
wires in the 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.
34 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.
1 Normal operation (The vane is set to
horizontal regardless of remote control.)
2 Check 2 (left).
• Check the vane motor. (Refer to "9-6.
How to check the parts".)
• Check for breaking of wire or
connection failure of connector.
3 Normal operation (Each connector on
vane motor side is disconnected or
setting the fixed vanes by wired remote
controller.)
1 Replace batteries of wireless remote con-
troller.
2–4
Check contact failure of each connector.
If no problems are found of connector,
replace indoor controller board.
When the same trouble occurs even
if indoor controller board is replaced,
replace wireless remote controller board.
24
Countermeasure