Hitachi FS3 Series, Service Manual

Page: 65 / 240

1
TROUBLESHOOTING
57
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.
Restart operation.
Does it trip soon?
Yes No
Turn off power and disconnect
U, V, W from compressor
terminals.
Turn ON #1 of DSW1 on
PCB3 and restart. Does it trip?
No
Check the inverter
circuit board. 3*)
Faulty
Replace the inverter
circuit board.
No Good
It trips
immediately
Yes If trips.
Is there any cause of
instantaneous
voltage decrease?
No
Check the
compressor.
It trips after a
certain period.
Yes
Check the power
source capacity.
It trips
occasionally.
Check the transistor
module. 2*)
Faulty
Replace the transistor
module.
Good
Replace the inverter
circuit board.
Is the compressor running
current as same as rated
current?
Yes
Check the compressor.
No
Check the diode
module. 1*)
Faulty
Replace the diode
module.
Good
Yes
(Input currents nearly equal (
–
3%).)
Are the input currents of
three phases nearly
equal? ( ±3%)
Replace the inverter
circuit board.
No
(Input currents out of balance.)
Check the power
supply.
Is the supply voltage
380-415V ±10%?
No
Yes
Is it 320V or more during
operation?
No
Check the capacity and
wiring of the power
source.
Yes
Is it 320V or more during
operation when other
devices are operating?
No
Replace the inverter
circuit board.
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.