Hitachi FS3 Series, Service Manual

Page: 62 / 240

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54
TROUBLESHOOTING
Alarm Code
47
Activation to Protect System from Excessively Low Suction Pressure
(Protection from Vacuum Operation)
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?
No
Correctly charge refrigerant.
Yes
Is the outdoor stop valve open?
No
Open the stop valve.
Yes
Is refrigerant leaking?
Yes
Repair leaks.
No
Is suction pressure sensor normal?
No
Replace suction pressure sensor if
faulty.
Yes
Are the electronic ex. valves fully
closed and locked?
Yes
Check connection of the connectors
and the circuit board. Replace the
electronic ex. valves if faulty.
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.
Note: In the case of H-LINK system,
check the refrigerant system setting
of the outdoor PCB and indoor PCB.
Phenomenon Cause Check Item
Action
(Turn OFF main switch)
Shortage of Ref.
Check ref. charged volume
or check for leakage.
Repair leakage and
correctly charge.
Closed Stop Valve Check stop valve. . Open stop valve.
Abnormal Low or High
Pressure Sensor
Check connector for PCB.
Replace pressure sensor if
faulty.
Incorrect Connection between
Indoor Unit and Outdoor Unit
Check electrical system and
ref. cycle.
Correctly connect between
indoor unit and outdoor unit.
Excessively Low
Suction Pressure
(in Vacuum)
Locked Ex. Valve Check connector for PCB. .
Repair or replace connector
of PCB or ex. valve.