Hitachi EV-1.5N1, Service Manual

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8. Troubleshooting
231
SMGB0079 rev.0 - 01/2013
8
Alarm code
45
Activation of high pressure increase protection device
• 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 the high-pressure sensor normal?
Yes
Are expansion valves fully
closed and locked?
Check if indoor or outdoor intake
air temperature is too high.
Check O.U. PCB1 or
connection of O.U. PCB1.
Replace the electronic
expansion valves if faulty.
Check connection of
the O.U. PCB1. Replace the
high-pressure sensor if faulty.
Open the stop valve.
No
Is there a leakage of the
solenoid valves (SVA)?
Replace the solenoid valve (SVA)
if faulty.
No
No
Yes
Are electric wiring and refrigerant
piping connections between
the indoor and outdoor unit
incorrectly connected?
Is the outdoor unit stop valve
closed?
No
No
Yes
Yes
Correctly connect it.
Check the outdoor electronic expansion valve during cooling
and the indoor electronic expansion valve during heating.
Yes
Cause Check Item
Action
(Turn OFF Main Switch)
Phenomenon
Excessively
High Discharge
Pressure
Check stop valve. Open stop valve. Closed Stop Valve
Check outlet temp. of
solenoid valve (SVA).
Check connection.
Replace solenoid valve
(SVA) if faulty.
Leakage of Solenoid Valve
(SVA)
Check thermistor for
indoor unit and outdoor
unit inlet air temp.
Replace inlet air
thermistor if faulty.
Excessively High
Temperature of Inlet Air for
Outdoor Unit or Indoor Unit
Check connecting
condition and output
voltage of connector
“CN100” (on O.U. PCB1)
for high pressure sensor.
Replace high pressure
sensor if faulty.
Abnormal High Pressure
Sensor
Check condition of
connector “CN100”
on O.U. PCB1.
Correctly connect.
Incorrect Connection between
Indoor Unit and Outdoor Unit
Repair connector
for O.U. PCB1 or
expansion valve.
Replace it if faulty.
Locked Expansion Valve
with Fully Closed
Check electrical system
and ref. cycle system.