Hitachi FSG Series Service Manual page 65

Alarm Code
52
Protection Activation Against Instantaneous Overcurrent of Inverter (2)
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 instantaneous overcurrent tripping occurs 3 times including 3 in 30
minutes. Retry operation is performed up to the occurrence of 2 times.
Conditions: Inverter current is 150% of the rated current.
No
Restart operation.
Does it trip soon?
It trips
No
immediately
It trips after a
certain period.
It trips
occasionally.
Is the compressor running
current as same as rated
current?
No
Check the diode
module. 1*)
Good
Are the input currents of
three phases nearly
equal? ( ±3%)
Is the supply voltage
380-415V ±10%?
Yes
Is it 320V or more during
operation?
Yes
Is it 320V or more during
operation when other
devices are operating?
Yes
1*): Regarding or replacing the checking method for the diode module, refer to page 1-92.
2*): Regarding the checking method for transistor module, refer to page 1-91.
3*): Regarding the checking of inverter components, refer to page 1-90 regarding electrical discharge.
Turn off power and disconnect
Yes
U, V, W from compressor
terminals.
Turn ON #1 of DSW1 on
PCB3 and restart. Does it trip?
Yes If trips.
Check the transistor
module. 2*)
Good
Yes
Faulty
Yes
(Input currents nearly equal (– 3%).)
No
(Input currents out of balance.)
No
No
No
TROUBLESHOOTING
No
Check the inverter
circuit board. 3*)
Good
Is there any cause of
instantaneous
voltage decrease?
Yes
Faulty
1
57
Faulty
Replace the inverter
circuit board.
No
Check the
compressor.
Check the power
source capacity.
Replace the transistor
module.
Replace the inverter
circuit board.
Check the compressor.
Replace the diode
module.
Replace the inverter
circuit board.
Check the power
supply.
Check the capacity and
wiring of the power
source.
Replace the inverter
circuit board.