TROUBLESHOOTING
22
9
9-1. Cautions on troubleshooting
1. Before troubleshooting, check the following:
(1) Check the power supply voltage.
(2) Check the indoor/outdoor connecting wire for mis-wiring.
2. Take care the following during servicing.
(1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and then after con-
firming the horizontal vane is closed, turn OFF the breaker and / or disconnect the power plug.
(2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the electronic
control P.C. board.
(3) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the com-
ponents.
(4) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
MUCF-GA35VB MUCF-GA50VB MUCF-GA60VB
3. Troubleshooting procedure
(1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality. To
make sure, check how many times the abnormality indication is flashing on and off before starting service work.
(2) Before servicing that the connector and terminal are connected properly.
(3) If the electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and the
components for bursting and discoloration.
(4) When troubleshooting, refer to the flow chart on this page.
9-2. Instruction of troubleshooting
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Indoor unit
doesn't
receive the
signal from
remote
controller.
OPERATION
INDICATOR
lamp on the
indoor unit is
flashing
on and off.
Outdoor unit
operates only
in Test Run
operation.
w
1
Outdoor unit
doesn't
operate
even in
Test Run
operation.
w
1
Indoor unit
operates when
the
EMERGENCY
OPERATION
switch is
pressed.
Indoor unit
doesn't
operate
when the
EMERGENCY
OPERATION
switch is
pressed.
Check room
temperature
thermistor.
Refer to
"Test point
diagram and
voltage".
Check of
wiring
diagram of
outdoor
unit on
page 8.
w
2
Refer to
"Check of
remote
controller
and receiver
P.C. board".
Refer to
"Check of
indoor
electronic
control
P.C. board".
2-time flash
Cause:
Indoor unit
• Trouble of
room
temperature/
indoor coil
thermistor
Check room
tempreture
thermistor and
indoor coil
thermistor.
Refer to
"Test point
diagram and
voltage".
When the
remote
controller is
pressed
or when the
EMERGENCY
OPERATION
switch is
pressed,
the fan doesn't
rotate, with
OPERATION
INDICATOR
lamp on.
Refer to
"Check of
indoor fan
motor".
Refer to indoor unit service manual.
w
2 Before checking the outdoor unit, make sure if any signal or
power is being transmitted from the indoor unit.
4-time flash
Cause:
Indoor unit
• Trouble of
indoor unit
control
system
Replace the
indoor
electronic
control
P.C. board.
w
1 "Test Run operation" means the operation within 30 minutes after EMERGENCY OPERATION
switch is pressed.
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