Hitachi FSXN Series Service Manual page 225

8 Troubleshooting
47
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 suction pressure (Ps) is lower than 0.09 MPa for more than twelve minutes and this
condition occurs three or more times in one hour.
Is the amount of refrigerant correctly?
Yes
Is the outdoor stop valve open?
Yes
Is refrigerant leaking?
No
Is suction pressure sensor normal?
Yes
Are the electronic expansion valves
fully closed and locked?
No
Check the indoor expansion valve during cooling
and the outdoor expansion valve during heating.
Check if connections of electric wiring
and refrigerant piping between the indoor
and outdoor unit are wrong.
Phenomenon
Abnormal Low or High
Pressure Sensor
Excessively
Low Suction
Incorrect Connection
Pressure
between Indoor Unit and
(in Vacuum)
Outdoor Unit
Locked Expansion Valve
with Fully Closed
Closed Expansion Valve by
Disconnecting Td Thermistor
Faulty Outdoor Fan Motor
Internal
Thermostat for
Outdoor Fan
is Activated
Faulty
in Heating
Internal
Operation
Thermostat
219
SMGB0065 rev. 1 - 12/2010
Activation of the low pressure decrease protection device (Vacuum operation protection).
No
No
Yes
No
Yes
NOTE:
In the case of H-LINK system, check the refrigerant
system setting of the outdoor PCB1 and indoor PCB.
Cause
Shortage of Ref.
Closed Stop Valve
Measure coil resistance
and insulation resistance.
Fault
Incorrect
Contact
Incorrect
Connection
PCB1: Control PCB in Outdoor Unit
PCB: Indoor Unit PCB
Correctly charge refrigerant.
Open the stop valve.
Repair leaks.
Replace suction pressure sensor
if faulty.
Check connection of the connectors
and the circuit board. Replace the
electronic expansion valves if faulty.
Check Item
(Turn OFF Main Switch)
Check ref. charged
volume or check for
leakage.
Check stop valve.
Check connector
for PCB1.
Check electrical
system and ref. cycle.
Repair connector for
Check connector for
PCB or expansion valve.
PCB.
Replace it if faulty.
Check Td thermistors
for compressors and
measure Td thermistor
resistance.
Check for conduction
after temperature of
outdoor fan motor is
decreased.
Measure resistance
by tester.
Check connection.
Action
Repair leakage and
correctly charge.
Open stop valve.
Replace pressure
sensor if faulty.
Correctly connect
between indoor unit
and outdoor unit.
Repair or replace
Td thermistor.
Replace outdoor fan
motor if faulty.
Replace outdoor fan
motor.
Remove looseness
and replace connector.
Connect correctly.
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