Hitachi RAS-18FSXN - Page 185

Cause Check Item
Action
(Turn OFF Main Switch)
Measure voltage
by tester.
Supply power.
Phenomenon
Short Circuit between
Wires
Melted Fuse for
Power Source
or Activation of
Breaker
(Outdoor Unit
and CH Unit)
Power Failure or No Power Supply
Check for breakage
of insulation.
Remove short circuit
and replace fuse.
Short Circuited Wire
to Ground
Remove short circuit to
ground and replace fuse.
Fault Outdoor Unit
Fan Motor
Measure resistance
between wires and
insulation resistance.
Replace outdoor unit
fan motor and fuse.
Faulty Comp. Motor
Measure resistance
between wires and
insulation resistance.
Replace comp. and fuse.
Measure insulation
resistance.
Short Circuit between
Wires
Melted Fuse for
Control Circuit
or Activation
of Breaker
(Outdoor Unit
and CH Unit)
Check for breakage
of insulation.
Remove short circuit
and replace fuse.
Short Circuit of Control
Circuit (to Ground)
Remove short circuit
and replace fuse.
Failure of Outdoor Unit
Fan Motor
Measure resistance
between wires and
insulation resistance.
Replace the AC chopper
for outdoor fan, fan
motor ad fuse.
Faulty Solenoid Coil
for Magnetic Switch
for Comp. Motor
Measure resistance
of coil.
Replace magnetic switch
and fuse.
Check continuity and
looseness of connection
screws.
Replacing Wires,
Repairing and
Tightening Screws
Check terminal Nos.
Correctly Connect
Wires
Measure insulation
resistance.
Check connections. Correctly connect wires.
Replace it if faulty.
Measure PCB1
output voltage *1)
Replace PCB1.PCB1 Power Circuit Failure
Check for unit number
setting of RSW on
Indoor PCB
Set unit number
correctly by RSW on
Indoor PCB.
Incorrect Setting of Indoor Unit Number
Between Outdoor Unit
and Indoor Unit
Disconnected
Wires Insufficient
Contacting or
Incorrect
Connection
Check continuity of
wires.
Check for looseness
of connection screws.
Check terminal Nos.
Replacing wires,
repairing, tightening
screws and correct
wiring.
Power Source Wiring
for Outdoor Unit
Disconnected Wires
to PCB
Faulty PCB
(Outdoor Unit,
Indoor Unit)
Faulty PCB
Disconnected Wire
Insufficient Contacting
Incorrect Wiring
Incorrect Wiring
*1): 12VDC between VCC12 and GND2, 5VDC between VCC05 and GND1,
12VDC between VCC12 and GND1, 15VDC between VCC15 and GND1,
24VDC between VCC24 and GND1, 12VDC between VCC12T and GND1GND1
8 Troubleshooting
179
SMGB0065 rev. 1 - 12/2010
8