
10 Troubleshooting
Troubleshooting procedure
SMGB0091 rev.2 - 11/2015
235
10
Alarm code
48
Overcurrent protection activation
Turn OFF power and disconnect
U, V, W from compressor
terminals. Turn ON number 1 of
DSW1 on DIP-IPM (4-6HP) or PCB4
(8/10HP) and restart. Does it trip?
*1)
Yes
Restart operation
after applying
current
Charge refrigerant
correctly
Restart expansion
valve
Check the
compressor
Is pressure
excessively high?
No
Yes
Check the stop
valves and
expansion valve
No
Restart operation.
Does it trip soon?
Yes
Check the
compressor
Check the power
source capacity
Replace the
DIP-IPM (4-6HP) or
PCB4 (8/10HP). *1)
Is there any cause of
instantaneous voltage
decrease?
No
No
Yes
Yes, it trips
It trips
immediately
It trips after a
certain period
Is the power supply voltage 380V ±10% or 415V ±10%?
Check the capacity
and wiring of the
power source
Is it 340V or more during operation when other devices
are operating?
Is the compressor running current the same as rated
current?
Is current applying to
crankcase heater?
Is refrigerant charged
excessively?
Yes
Yes
Yes
Yes
Yes
No
Is lock of indoor expansion valve
opened at cooling operation?
Is lock of outdoor expansion valve
opened at heating operation
Yes
Check for clogging
at heat exchanger
Check the fan
No
No
No
No
Is the power supply voltage 323V during operation?
?
N O T E
*1): Perform the high voltage discharge work by referring to sections