10 Troubleshooting
Initial troubleshooting
SMGB0091 rev.2 - 11/2015
190
Phenomenon
Cause
Check item
Action
(Turn OFF the main switch)
Indoor fan speed does not
change
Failure of the
discharge air
temperature
thermistor
Failure of the
thermistor
Check the thermistor using
the self-check mode *1)
Replace or correctly connect
the wiring when it is abnormal
Disconnected
wire of the
thermistor
Failure of the remote control switch
Check it using the self-check
mode *2)
Replace if it failed
Failure of PCB for the indoor unit
Replace if PCB fails
No defrost operation mode is
available during the heating
process or the defrost
operation continues
Failure of
thermistor
for RASC
evaporating
temperature
during heating
Failure of
thermistor
Replace or correctly connect when it is abnormal
Disconnected
wire of
thermistor
Failure of
4-way valve
Disconnec ted
4-way valve coil
Measure the resistance of
coil
Replace the 4-way valve
Incorrect
activation of
4-way valve
Enforced power supply
Disconnected control wires between
indoor unit and RASC unit
Check the connectors
Correctly connect the wiring
Failure of the
RASC units of
PCB
Disconnected
wiring to PCB
Check the connectors
Correctly connect the wiring
Failure of PCB
Check PCB using the self-
check mode *2)
Replace PCB when the check
mode is not available
Failure of the
indoor unit of
PCB
Disconnected
wiring to PCB
Check the connectors
Correctly connect the wiring
Failure of PCB
Check PCB using the self-
check mode *2)
Replace if PCB fails
The LED and the LCD on the
remote control switch remain
ON
Failure of PCB in the indoor unit or
the remote control switch
?
N O T E
*1): Refer to section
“Self-checking procedure of the remote control switch”
.
*2): Refer to section
“Self-checking procedure of PCB by means of the remote control switch”