Hitachi UTOPIA RAS-4HVRP2E - Checking the Electrical Wires and the Power Source; Ras-(4-6)H(V)(R;N)(C;P)2 E

10 Troubleshooting
Initial troubleshooting
SMGB0136 rev.0 - 07/2021
217
10
Phenomenon Cause Check item
Action
(Turn OFF the main switch)
Cooling or heating
process with an
abnormal sound
Foreign particles inside of the fan casing Visually inspect it Remove the foreign particles
Outdoor unit propeller fan is hitting the
shroud
Visually inspect it
Adjust the position of the
propeller fan
Abnormal
sound from the
compressor
Faulty Installation
Check that each part is tightly
xed
Tightlyxeachpart
Liquid refrigerant
compression
Adjust the suction gas
temperature and pressure
Ensure superheat
Wear or breakage of
the internal compressor
parts
Abnormal sound from the
inside of the compressor
Replace the compressor
No heating by the oil
heater
Check the resistance (oil
heater, fuse)
Replace the oil heater or the
fuse
Humming sound from the magnetic
conductor
Check the surface of the
contacts
Replace the magnetic switch
Abnormal vibration of the cabinets Checkeachxingscrew Tightlyxeachscrew
Outdoor fan does not
operate when the
compressor operates
Obstacle at the outdoor fan Check the obstacles Remove the obstacles
Watching condition for the heating process
Wait for the switching of the
4-way valve (1 ~ 3 minutes)
If the 4-way valve does not
switch,checkforinsufcient
refrigerant
10.1.2 RAS-(4-6)H(V)(R/N)(C/P)2E
10.1.2.1 Checking the electrical wires and the power source
No. Item to check Check method
1
Is the power source breaker
or the fuse blown out?
Check the voltage (secondary side) of the breaker and using a tester, check the conductivity of
the fuse.
2
Is the electrical wiring
properly secured and are
the connections correctly
xed?
Check that the following wiring connection on outdoor unit/indoor unit PCBs is not loosened.
- The connection for thermistors
- The connection for the communication cable.
- The communication cable connects to a terminal block at the outdoor unit / indoor unit not
PCB.
- Power supply wiring is connected to a terminal block, not PCB.
- Each connection for power source line.
Check that the wiring connections on outdoor unit and indoor unit PCBs is not loosened or
misconnected on the site according to “Electrical Wiring Diagram” of the technical catalogue.
? NOTE
If the fuse on an indoor unit PCB is blown, diagnose the cause of overcurrent and replace the fuse(s). In addition, check the power source
of optional parts because the fuses may blow out by the power source failure. Turn off power for safety.