Hitachi UTOPIA RAS-4HVRP2E Service Manual page 242

10 Troubleshooting
Troubleshooting procedure
Phenomenon
Power failure or power is not ON
Blown out fuse for the power
source or activation of the
outdoor unit breaker
Blown out fuse for control
circuit or activation of outdoor
unit breaker
PCB1 Power circuit failure
Disconnected wires insufficient
contacting or incorrect
connection
Faulty PCB (outdoor unit,
indoor unit)
Incorrect wiring
?
N O T E
• *1) In the case that the end terminal resistance (DSW5-1) is set to OFF for H-LINK connection, set the end terminal resistance to ON
when CN8 is disconnected. Set the end terminal resistance to OFF when CN8 is reconnected.
• *2) Transmission Setting (SW1)
• *3)
PCB1 output voltage
Vcc 12 - GND2
Vcc 05 - GND1
Vcc 12 - GND1
Vcc 15 - GND1
Vcc 24 - GND1
Vcc 12T - GND1
240 SMGB0136 rev.0 - 07/2021
Cause
Short-circuit between the wires
Short-circuited wire to ground
Faulty compressor motor
Failure of outdoor unit fan
motor
Short-circuit between the wires
Short-circuit of the control
circuit (to ground)
Faulty solenoid coil for the
magnetic switch for the
compressor motor
Failure of outdoor unit fan
motor
Between outdoor unit and
indoor unit
Power source wiring for the
screws and the correct wiring
outdoor unit
Disconnected wires to PCB
Faulty PCB
Disconnected wire; insufficient
contacting
Incorrect wiring
Voltage
12VDC
5 VDC
12 VDC
15 VDC
24 VDC
12 VDC
Check item
Measure the voltage by means
of the tester
Check the insulation material
for breaks
Measure the insulation
resistance
Measure the resistance
between the wires and the
insulation resistance
Measure resistance between
wires and insulation resistance
Check the insulation material
for breaks
Measure the insulation
resistance
Measure the resistance of coil
Measure the resistance
between the wires and the
insulation resistance
PCB1 Measure output voltage
*1)
Check the continuity of the
wires
Check for looseness of the
connection screws
Check the terminal numbers
Check the connections
—
Check the continuity and
the looseness of connection
screws
Check the terminal numbers
Action
(Turn OFF the main switch)
Supply the power
Remove the short-circuit and
replace the fuse
Remove short-circuit to ground
and replace the fuse
Replace the compressor and
the fuse
Replace the outdoor unit fan
motor and the fuse
Remove the short-circuit and
replace the fuse
Remove the short-circuit and
replace the fuse
Replace the magnetic switch
and the fuse
Replace the outdoor unit fan
motor and fuse
Replace PCB1
Replacing wires repairing and
tightening the power source
wiring for the screws and the
correct wiring
Correctly connect the wires
Replace PCB if faulty
Replacing wires, repairing and
tightening the screws
Correctly connect the wires