Hitachi RAS-(4-12)HNP(1)(E) - Activation of High Pressure Increase Protection Device

8 Troubleshooting
258
SMGB0087 rev.0 - 12/2013
Alarm code
45
Activation of high pressure increase protection device
- 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)?
Replace the solenoid valve
(SVA) if faulty
Yes
No
Is the outdoor unit stop valve
closed?
Open the stop valve
No
Check if indoor or outdoor intake air
temperature is too high
Correctly connect it
Yes
No
Is the high-pressure
sensor normal?
Yes
Are expansion valves fully
closed and locked?
No
No
Are electric wiring and
refrigerant piping connections
between the indoor and outdoor
unit incorrectly connected?
Check the outdoor electronic expansion valve during cooling
and the indoor electronic expansion valve during heating.
Check connection of the OU
PCB1. Replace the high-
pressure sensor if faulty
Check OU PCB1 or
connection of OU PCB1.
Replace the electronic
expansion valves if faulty
Yes
Yes
Phenomenon Cause Check item
Action
(Turn OFF the main switch)
Excessively
high discharge
pressure
Leakage of solenoid valve (SVA)
Check the outlet
temperature of solenoid
valve (SVA)
Check connection. Replace
solenoid valve (SVA) if faulty
Closed stop valve
Check stop valve Open stop valve
Abnormal high pressure sensor
Check connecting
condition and output
voltage “CN100” (on
OU PCB1) for high
pressure sensor
Replace high pressure
sensor if faulty
Excessively high temperature of
inlet air for outdoor unit or indoor
unit
Check thermistor for
indoor unit and outdoor
unit inlet air tempera-
ture
Replace the inlet air
thermistor if faulty
Incorrect connection between
indoor unit and outdoor unit
Check electrical
system and refrigerant
cycle system
Correctly connect
Locked expansion valve with fully
closed
Check condition of
connector “CN100” on
OU PCB1
Repair connector for OU PCB1
or expansion valve. Replace
if faulty