Hitachi FSXN Series Service Manual page 206

8 Troubleshooting
21
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 pressure sensor voltage decreases lower than 0.1V or increases higher than 4.9V
during the operation.
Is the connection CN7
of the outdoor unit
PCB1 abnormal?
No
Is 12 VDC applied
across #1 and #3 of the
connector CN7 of the
outdoor unit PCB1?
Yes
Is voltage under
0.1 VDC or over 4.9VDC
across #2 and #3 of the
connector CN7 of the
outdoor unit PCB1?
Yes
Is the Check Joint
Clogged?
No
Abnormality of High
Pressure Sensor.
Phenomenon
Faulty High
Pressure Sensor
Faulty PCB1
Indicated
Malfunction of Pressure
Pressure Value
Sensor due to Faulty
is Excessively
Check Joint
High or Low
200
SMGB0065 rev. 1 - 12/2010
Abnormal operation of the high pressure sensor of the outdoor unit.
Yes
No
No
Yes
Cause
Fault
Incorrect Connection
PCB1: Control PCB in Outdoor Unit
Connect correctly.
Faulty PCB1.
Faulty PCB1.
Replace check joint.
Check Item
(Turn OFF Main Switch)
Check output voltage
is correct.
Check connections.
Replace PCB1 and
check operation.
Check for clogging
of check joint.
Action
Replace pressure
sensor if faulty.
Repair wiring and
connections.
Replace PCB1 if faulty.
Replace check joint.