
10 Troubleshooting
Troubleshooting procedure
SMGB0091 rev.2 - 11/2015
218
Alarm code
11
Abnormal operation of thermistor for the indoor unit air inlet temperature
(air inlet thermistor)
This alarm code is displayed when the thermistor is short-circuited (less than 0.24 kΩ) or cut (greater than 840 kΩ) during
the cooling process or the heating process. The system is automatically restarted when the fault is removed.
Is THM1 (inlet) connected to the
indoor unit PCB?
Connect it
No
Yes
Is the resistance of THM1
between 0.24kΩ and 840kΩ?
Faulty thermistor
No
Yes
Faulty PCB
Phenomenon
Cause
Check item
Action
(Turn OFF the main switch)
Faulty air inlet thermistor
Fault
Check the resistance
Replace the thermistor if faulty
Incorrect connection
Check the connection
Repair the wiring and the
connections
Faulty PCB
Replace PCB and check the
operation
Replace PCB if faulty
?
N O T E
This data is applicable to the following thermistors:
• Indoor unit discharge air temperature.
• Indoor unit liquid refrigerant temperature.
• Indoor unit air inlet temperature.
• Outdoor temperature.
• RASC unit evaporating temperature.
• Indoor unit gas piping.
Thermistor
resistance
(kΩ)
Air temperature (ºC)
Thermistor characteristics
Examples of position of the indoor unit air inlet thermistor (THM1)
THM1
THM1
THM1