Hitachi RAS-2-HVNP Service Manual page 233

8. Troubleshooting
19
Alarm code
• The RUN LED flickers and "ALARM" is displayed on the remote control switch.
• The unit number, the alarm code and the unit code are alternately displayed on the set temperature section.
The unit number and the alarm code are displayed on the display of the outdoor unit PCB1.
- This alarm code is displayed when the following conditions occurs three times in 30 minutes. Indoor fan rotates less
than 70 rpm for 5 seconds during operation.
• Set air flow volume "Hi" before starting this check.
Occurrence of
Alarm Code "19"
Check connectors PCN500
NOTE:
and PCN550 on I.U. PCB.
Turn OFF the power source securely
before connector checking.
If not, it may cause DC fan motor failure.
(Built-in PCB for DC fan motor may be damaged.)
Check that 220/240V is
applied between
L1 and N of TB1.
Yes
Is LED4 on
I.U. PCB OFF?
(*1)
No
Is LED1 on
I.U. PCB OFF?
(*2)
No
Is DC power
output of I.U. PCB
normal? (*3)
Yes
Is DC power
output of I.U. PCB
normal? (*4)
Yes
Is fan motor
speed control command to
fan motor sent correctly?
(*5)
No
Faulty I.U. PCB
Replace I.U. PCB.
219
SMGB0079 rev.0 - 01/2013
Activation of the protection device for the indoor fan motor (RPK)
Perform the following check after setting
the air flow volume to "HIGH".
A high voltage is applied to electrical parts.
Perform the check carefully to prevent
an electric shock.
(*1)
The electrical source for I.U. PCB
is not supplied when LED4
Yes
is turned OFF.
Faulty I.U. PCB
(*2)
Abnormal voltage is supplied
Yes
for fan motor.
Faulty I.U. PCB
(Normal Voltage: DC280V)
(*3)
Measure the voltage between
No
VCC15 and VDC (15V+10%) by tester.
Faulty I.U. PCB
(*4)
Measure the following voltage of each check point by a tester.
Between VCC05 and GND: 5V+4%
No
Between VCC13 and GND: 13.1V+10%
Faulty I.U. PCB
(*5) Perform the operation with PCN550 on I.U. PCB disconnected.
Yes
No
Does Fan
Faulty Fan Motor
Motor run?
(*6) Perform the operation with PCN550 on PCB connected.
Yes
Yes
Is speed pulse
Faulty I.U. PCB
signal to I.U. PCB
sent correctly?
(*6)
No
Replace Fan Motor.
Faulty Fan Motor
PCN550
PC4-2
PC4
VCC15
+
LED1
VDC
It functions normally if more than 1V generates between No.4
pin of PCN550 and VDC- (check point) for approx. 10 seconds
after starting the operation.
(NOTES)
1. Even if the operation is stopped, 0.3 to 0.4V may be generated.
2. The voltage may not be generated sequentially after 10 seconds
from starting the operation to perform the operation "#".
(*5)
It functions normally if several voltages are generated between
No.2 pin of PC4 and VDC- (check point).
(NOTE)
Even if the operation is stopped, approx. 0.2V may be generated.
(*6)
GND1
+
VCC1
+
+
VCC05
PCN500
Replace I.U. PCB.
Replace I.U. PCB.
Replace I.U. PCB.
Replace I.U. PCB.
Replace Fan Motor
Replace I.U. PCB.
8