Hitachi RAS-2-HVNP Service Manual page 245

8. Troubleshooting
45
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 PCB.
- When the compressor is operated with the discharge pressure (Pd) higher than 3.8MPa for 1 minute, the retry
operation is performed 3 minutes after all compressors are stopped. Thereafter, this alarm code is indicated when
above abnormality is detected twice in 30 minutes.
Is there a leakage of the
solenoid valves (SVA)?
Is the outdoor unit stop valve
closed?
Is the high-pressure sensor normal?
Are expansion valves fully
closed and locked?
Are electric wiring and refrigerant
piping connections between
the indoor and outdoor unit
incorrectly connected?
Check if indoor or outdoor intake
air temperature is too high.
Phenomenon
Excessively
High Discharge
Pressure
231
SMGB0079 rev.0 - 01/2013
Activation of high pressure increase protection device
Yes
No
Yes
No
No
Yes
Yes
No
Check the outdoor electronic expansion valve during cooling
and the indoor electronic expansion valve during heating.
Yes
No
Cause
Leakage of Solenoid Valve
(SVA)
Closed Stop Valve
Abnormal High Pressure
Sensor
Excessively High
Temperature of Inlet Air for
Outdoor Unit or Indoor Unit
Incorrect Connection between
Indoor Unit and Outdoor Unit
Locked Expansion Valve
with Fully Closed
Replace the solenoid valve (SVA)
if faulty.
Open the stop valve.
Check connection of
the O.U. PCB1. Replace the
high-pressure sensor if faulty.
Check O.U. PCB1 or
connection of O.U. PCB1.
Replace the electronic
expansion valves if faulty.
Correctly connect it.
Check Item
Check outlet temp. of
solenoid valve (SVA).
Check stop valve.
Check connecting
condition and output
voltage of connector
"CN100" (on O.U. PCB1)
for high pressure sensor.
Check thermistor for
indoor unit and outdoor
unit inlet air temp.
Check electrical system
and ref. cycle system.
Check condition of
connector "CN100"
on O.U. PCB1.
Action
(Turn OFF Main Switch)
Check connection.
Replace solenoid valve
(SVA) if faulty.
Open stop valve.
Replace high pressure
sensor if faulty.
Replace inlet air
thermistor if faulty.
Correctly connect.
Repair connector
for O.U. PCB1 or
expansion valve.
Replace it if faulty.
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