Hitachi RASC-4HNPE Service Manual page 243

10 Troubleshooting
Troubleshooting procedure
45
Alarm code
When the compressor operates with the discharge pressure (Pd) higher than 3.8 MPa for 1 minute, the retry operation
is performed 3 minutes after compressor is 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 RASC unit stop valve
Is the high-pressure sensor
Are expansion valves fully closed
Are electric wiring and
refrigerant piping connections
between the indoor and RASC unit
incorrectly connected?
Check if indoor or outdoor intake air
temperature is too high
Phenomenon
Leakage of solenoid valve (SVA)
Abnormal high pressure sensor
Excessively
Excessively high temperature of
high discharge
inlet air for RASC unit or indoor
pressure
Incorrect connection between
indoor unit and RASC unit
Locked expansion valve with fully
Faulty RASC fan motor
?
N O T E
(*): When the alarm code "45" is indicated, the RASC fan motor may be damaged. Ensure that fan motor is checked according to the
section "10.4.3 Fault diagnosis of fan
233 SMGB0091 rev.2 - 11/2015
Activation of high pressure increase protection device
Yes
No
Yes
closed?
No
No
normal?
Yes
Yes
and locked?
No
Check the RASC electronic expansion valve during cooling
and the indoor electronic expansion valve during heating.
Yes
No
Cause
Closed stop valve
unit
closed
motor".
Replace the solenoid valve
(SVA) if faulty
Open the stop valve
Check connection of the
RASC PCB1. Replace the
high-pressure sensor if
faulty
Check RASC PCB1 or
connection of RASC PCB1.
Replace the electronic
expansion valves if faulty
Correctly connect it
Check item
Check the outlet
temperature of solenoid
valve (SVA)
Check stop valve
Check connecting condition
and output voltage "CN100"
(on RASC PCB1) for high
pressure sensor
Check thermistor for indoor
unit and RASC unit inlet air
temperature
Check electrical
system and refrigerant
cycle system
Check condition of
connector "CN100" on
RASC PCB1
Measure coil resistance
and insulating resistance (*)
Action
(Turn OFF the main switch)
Check connection. Replace
solenoid valve (SVA) if faulty
Open stop valve
Replace high pressure sensor
if faulty
Replace the inlet air thermistor
if faulty
Correctly connect
Repair connector for RASC
PCB1 or expansion valve.
Replace if faulty
Replace RASC fan motor if
faulty.
10