Hitachi FSG Series Service Manual page 62

1
TROUBLESHOOTING
54
Alarm Code
Activation to Protect System from Excessively Low Suction Pressure
47
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 a suction pressure is lower than 0.02 MPa (0.2 kg/cm²G) for over 12
minutes and its state occurs more than 3 times including 3 in one hour.
Is the amount of refrigerant correctly?
Yes
Is the outdoor stop valve open?
Yes
Is refrigerant leaking?
No
Is suction pressure sensor normal?
Yes
Are the electronic ex. valves fully
closed and locked?
No
Check the indoor ex. valve during cooling and the outdoor
ex. valve during heating.
Check if connections of electric wiring
and refrigerant piping between the
indoor and outdoor unit are wrong.
Phenomenon
Excessively Low
Suction Pressure
(in Vacuum)
Incorrect Connection between
Indoor Unit and Outdoor Unit
(Protection from Vacuum Operation)
No
No
Yes
No
Yes
Cause
Shortage of Ref.
Closed Stop Valve
Abnormal Low or High
Pressure Sensor
Locked Ex. Valve
Replace suction pressure sensor if
Check connection of the connectors
Note: In the case of H-LINK system,
check the refrigerant system setting
of the outdoor PCB and indoor PCB.
Check Item
Check ref. charged volume
or check for leakage.
Check stop valve. .
Check connector for PCB.
Check electrical system and
ref. cycle.
Check connector for PCB.
.
Correctly charge refrigerant.
Open the stop valve.
Repair leaks.
faulty.
and the circuit board. Replace the
electronic ex. valves if faulty.
Action
(Turn OFF main switch)
Repair leakage and
correctly charge.
Open stop valve.
Replace pressure sensor if
faulty.
Correctly connect between
indoor unit and outdoor unit.
Repair or replace connector
of PCB or ex. valve.