
10 Troubleshooting
Troubleshooting procedure
SMGB0091 rev.2 - 11/2015
222
Alarm code
15
Abnormal operation of thermistor for fresh outdoor air (Econofresh)
•
The RUN LED flickers and “ALARM” is displayed on the remote control switch.
• The unit number, the alarm code and the unit code are alternately displayed on the set temperature section. The unit
number and the alarm code are displayed on the display of the RASC unit PCB.
-
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 THM4 connected to (intake)
of PCB?
Connect it
No
Yes
Is the resistance of THM4
between 0.24kΩ and 840kΩ?
Faulty thermistor
No
Yes
Faulty PCB
Phenomenon
Cause
Check item
Action
(Turn OFF the main switch)
Faulty fresh outdoor air
(Econofresh) 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
Thermistor
resistance
(kΩ)
Air temperature (°C)
Thermistor characteristics