Hitachi FSXN Series Service Manual page 204

8 Troubleshooting
19
Alarm code
• The RUN indicator flashes and the ALARM indication is displayed on the remote control switch.
• The unit no., the alarm code and the unit code are alternatively displayed in the temperature setting section and the unit
no. and alarm code are displayed on the outdoor unit's PCB1 display.
* This alarm is indicated when the following conditions occur three times in 30 minutes:
* The indoor unit fan motor rotates less than 70 rpm for five seconds while it is operating.
Does the indoor
fan run?
No
Check the connector as
shown on the right. (*1)
Is LED4 on
PCB OFF?
No
Is DC power
supply for PCB
correctly? (*2)
Yes
Is DC power
supply (280V) for PCB
correctly? (*3)
Yes
Is DC power
supply (15V) for PCB
correctly? (*4)
Yes
Is fan motor
speed control command
to fan motor
correctly?
(*5)
Yes
Faulty Fan Motor
Replace Fan Motor
198
SMGB0065 rev. 1 - 12/2010
Activation of the protection device for the indoor unit fan motor (RPK models).
l Set air flow volume "Hi" before starting this check.
(*1): Turn OFF the power before checking the connectors.
If not, PCB and the fan motor may be damaged.
Also, the LED4 must be turned OFF
before starting this check to avoid electric shock.
PCB: CN550, CN500
Yes
Insufficient voltage for
Faulty PCB
micro-computer.
(*2)
Is the voltage between 5V
No
and GND of PCB 4.75 to 5.25V?
Faulty PCB
Is the voltage between 12V
and GND of PCB 11.9 to 12.8V?
(Use a tester.)
(Note)
(Refer to the figure below.)
(*3)
Is the voltage between CN550-#1 and
No
CN550-#3 of PCB 280V± 10%?
Faulty PCB
(Use a tester.)
(*4)
Is the voltage between CN550-#3 and
No
CN550-#4 of PCB 14.8V to 15.8V?
Faulty PCB
(Use a tester.)
No
Faulty PCB
(*5)
Disconnect CN550 on PCB when performing.
If 2V (or over) are applied between CN550-#5 to CN550-#3 on PCB
for 10 sec. (Approx.) after starting operation, the PCB is normal.
(Note)
PCB1: Control PCB in Outdoor Unit
PCB: Indoor Unit PCB
6
1
CN550
Use the following check points (writen in Japanese) on the PCB.
5V
: next to DSW5
12V
: next to HA connector
GND
: next to IC6 (do not use
The voltage may not be conducted sequentially
after 10 sec. to perform the above operation "*".
HA
12V
5V DSW5
15V
IC6
GND GND
CN500
PCB (Indoor Unit PCB)
Replace PCB
Replace PCB
)
Replace PCB
Replace PCB
Replace PCB