Hitachi SAMURAI Series Service Manual page 108

4 Troubleshooting
Troubleshooting by alarm code
C1-51
Alarm code
Alarm stop reason
The running current for one compressor is increased above the value for activation of the overcurrent relay, thus
activating the (thermal) overcurrent relay.
PCB monitoring position
PCBd (I/O PCB) PCN206
Operation control
results in immediate
activation of alarm
No
Overcurrent relay
(51C1) is activated
No
Check of PCB (I/O PCB)
d
100 SMGB0120 rev.0 - 11/2017
Compressor overcurrent
Yes
Overcurrent relay
(51C1) is being reset
Remove the
wiring inserted into
connector PCN206 on
PCB (I/O PCB) and mesure
d
conductivity. Is there
conductivity?
Check of PCB
d
I/O PCB is normal
Yes
No
Press the reset button of
the overcurrent relay
Yes
No
Check of overcurrent relay
Yes
(internal disconnection)
(I/O PCB)
Power source voltage too high or too low
Phase unbalance of the power source
voltage
Lock status of compressor motor
Decrease of insulation of compressor motor
Power source fuse
Loosening of screws of power source
terminal
Inspection of electromagnetic switches
(single phase operation)
Malfunction of slide valve of compressor
Check of wiring
(disconnection)