Hitachi RAS-3.5UFESNH1 - Page 25

2.TROUBLESHOOTING
Fault
code
Fault description
Possible reasons for abnormality
How to deal with Remarks
46
IPM and control board
communication fault
1.The cable between the control
board and the driver board is
connected loose
ly;
2.The cable between the control
board and the driver board
fails;
3.The driver board fails；
4.The control board fails.
1.Reconnect the cable between
the control board and the
driver board;
2.Replace the communication
cable between the control
board and the driver board;
3.Replace the driver board;
4.Replace the control board.
47
Too high discharge
temperature fault
1.
2.
The refrigerant of the unit is not
enough;
The refrigerant of the unit is not
enough due to that the
installation pipe is longer;
3.Throttling service fails;
4.The outdoor ambient temperature
is too high.
1.Check the welding point to
confirm whether the unit has
leakage point, and then add
some refrigerant;
2.Add some refrigerant referring
to the installation user manual;
3.Repl
ace the throttling service
(such as capillary, expansion
valve);
4.Normal protection.
48
The outdoor DC
fan motor fault
(upper fan motor)
1.The connecting wiring of the up
DC fan motor is loose;
2.The cord of the upper DC fan
motor fails;
3.The upper DC fan motor fails;
4.The drive circuit of the upper DC
fan motor fails;
5.The outdoor fan has been
blocked.
1.Reconnect the wiring of the up
DC fan motor;
2.Replace the upper DC fan motor;
3.Replace the upper DC fan motor;
4.Replace the driver board of the
fan motor;
5.Check the outdoor fan and ensure
the outdoor fan can run normally.
49
The outdoor DC
fan motor fault
(down fan motor)
1.
2.
The connecting wiring of the
down DC fan motor is loose;
The cord of the down DC fan
motor fails
;
3. The down DC fan motor fails;
4. The drive circuit of the down DC
fan motor fails;
5. The outdoor fan has been
blocked.
1. Reconnect the wiring of the
down DC fan motor;
2. Replace the down DC fan
motor;
3. Replace the down DC fan
motor;
4. Replace the driver board of
the fan motor;
5. Check the outdoor fan and
ensure the outdoor fan can run
normally.
91
The unit turn off due to
the IPM
board over heating
fault
1.
2.
The outdoor ambient temp. is too
high;
The speed of the out fan motor is
too low if the fan motor is
AC fan
motor;
3.The outdoor unit is not installed in
accordance with the standards;
4.The supply power is too low.
1.
2.
Normal protection;
Check the fa
n capacitor, and
replace the fan capacitor if it
fails;
3.
Reinstall the outdoor unit
referring to the installation
user manual;
4.Normal protection.
96
Lacking of
refrigerant
The refrigerant of the unit is not
enough.
Discharge the refrigerant and
charge the refrigerant
referring to the rating label.
97
4-way valve
commutation failure
fault
1.The connecting wiring of the 4-
way valve coil is loose;
2.The 4-way valve coil fails;
3.The 4-way v
alve fails;
4.The driver board of the 4-way
valve fails.
1. Reconnect the wiring of the
4-way valve;
2. Replace the 4-way valve coil;
3. Replace the 4-way valve;
4.Replace the driver board of the
4-way valve.
23