Hitachi RAS-(3-6)HVNC1(E) - Page 243

8 Troubleshooting
229
SMGB0087 rev.0 - 12/2013
8
Phenomenon Cause Check item
Action
(Turn OFF the main switch)
Power failure or no power supply
Measure the voltage
using the tester
Supply power
Melted fuse for
power source
or activation of
the outdoor unit
breaker
Short circuit between wires
Check for breakage of
insulation
Remove cause of short circuit.
Replace fuse and/or IU/OU
PCB if faulty
Short circuited wire to ground
Measure the insulation
resistance
Remove cause of short circuit
to ground.
Replace fuse and/or IU/OU
PCB if faulty
Faulty compressor motor
Measure the resistance
between the wires and
the insulation resistance
Replace compressor and fuse
(OU). Replace inverter PCB
and/or PCB1 if faulty. (OU)
Faulty outdoor unit fan motor
Measure the resistance
between the wires and
the insulation resistance
Replace the outdoor unit fan
motor and the fuse.
Replace OU PCB if faulty
Melted fuse
for DC power
supply (outdoor
unit) EF1, EF2
and EF3 on
PCB1 EF1 on
inverter PCB
Short circuit between wires
Check for breakage of
insulation
Remove cause of short circuit
and replace fuse.
Short circuit (to ground) of DC fan
power supply line
Measure the insulation
resistance
Remove the short circuit and
replace the fuse
Faulty solenoid coil for magnetic
switch (CMC) for compressor motor
Measure insulation
resistance
Remove cause of short circuit
and replace fuse
Failure of outdoor unit fan motor
Measure resistance be-
tween wires and insula-
tion resistance
Replace fan motor and fuse.
Incorrect power supply circuit of
OU PCB1
Check OU PCB1 output.
*3)
Replace fuse
Melted fuse
RS1, RS2
Faulty CB
Measurement of
insulation resistance
Replace IPM or CB
Faulty IPM
Measurement of resist-
ance between lines and
insulation resistance
Replace IPM or PCB2 IPM
Incorrect power supply circuit of OU PCB1
Measure OU PCB1
output. *3)
Replace OU PCB1
Disconnected
wires insufcient
contacting or
incorrect con-
nection
Between outdoor unit and indoor
unit
Check the continuity
of the wires. Check for
looseness of the con-
nection screws. Check
the terminal numbers
Replacing wires repairing and
tightening the screws and the
correct wiring
Power source wiring for the out-
door unit
Faulty PCB
(outdoor unit,
indoor unit)
Disconnected wires to IU/OU PCB Check the connections Correctly connect the wires
Faulty IU/OU PCB
Replace it if faulty
Incorrect wiring
Disconnected wire; insufcient
contacting
Check the continuity
and the looseness of
connection screws
Replacing wires, repairing and
tightening the screws
Incorrect wiring
Check terminal numbers Correctly connect wires