Hitachi FSG Series Service Manual page 42

1
TROUBLESHOOTING
34
Alarm Code
11
n "RUN" light flickers and "ALARM" is indicated on the remote control switch.
n The unit No., alarm code and the unit code is alternately indicated on the set temperature section, and the
unit No. and alarm code are indicated on the display of the outdoor unit PCB.
‘
This alarm code is indicated when the thermistor is short-circuited (less than 0.24 kW) or cut (greater than
840 kW) during the cooling or heating operation. The system is automatically restarted when the fault is
removed.
Is it connected to THM1
(intake) of PCB.
Yes
Is resistance of THM1
between 0.24kW and 840kW?
Yes
Faulty PCB
Phenomenon
Faulty Intake
Air Thermistor
Faulty PCB
Thermistor
Resistance
(KW)
Abnormality of Thermistor for Indoor Unit Inlet Air Temperature
(Air Inlet Thermistor)
No
Connect it.
No
Faulty Thermistor
.
Cause
Fault
Incorrect Connection
Ambient Temperature (°C)
Thermistor Characteristics
In case of 4-Way Cassette
Check Item
Check resistance.
Check connection.
Replace PCB and Check
operation
Note: This data is applicable to the following
thermistors:
1. Indoor Unit Discharge Air Temperature,
2. Indoor Unit Liquid Refrigerant Temperature
3. Indoor Unit Intake Air Temperature
4. Outdoor Air Temperature
5. Outdoor Unit Evaporating Temperature
6. Indoor Unit Gas Piping
Indoor Unit
Inlet Thermistor
Action
(Turn OFF main switch)
Replace thermistor if
faulty.
Repair wiring and
connections.
Replace PCB if faulty