Hitachi UTOPIA RAS-4HVRP2E - Page 287

10 Troubleshooting
Troubleshooting procedure
SMGB0136 rev.0 - 07/2021
285
10
Alarm code
45
Activation of High Pressure Increase Protection
• Thealarmcodeisashedonthe7-segmentdisplayoftheoutdoorunit.
• The alarm code is displayed on the wired controller of the indoor unit.
If the high pressure (Pd) of the compressor is more than 3.8 MPa for a minute, the compressor stops. The operation
automatically restarts after three minutes. If this occurs again twice in the next 30 minutes, this alarm code is displayed.
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
Phenomenon
Cause
Check Item
Action (Turn OFF
Main Switch)
Is the refrigerant leakage from
solenoid valve (SVA)?
Replace solenoid valve (SVA) if faulty
Are outdoor unit stop valve closed? Open Stop valves
Is high pressure sensor normal?
Check connection of Outdoor Unit.
Replace high pressure sensor if faulty
Are electronic explansion valves for
O.U./I.U. fully closed and locked?
Check O.U./I.U. PCB or connection of
O.U./I.U. PCB.
Replace electronic expansion valves if faulty.
Are communication cable and
refrigerant piping connections between
indoor and outdoor unit incorrectly
connected?
Correctly connect them
Check that indoor or outdoor inlet air
temperature is not too high.
? NOTE
In the case of H-LINK system, check the refrigerant system
number setting of the outdoor unit and indoor unit PCB.
Leakage from 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
(Fully Closed)
Excessively Increasing
High Pressure
Check outlet temp. of solenoid
valve (SVA)
Check stop valves
Check connecting condition
and output voltage of connector
CN100 (on O.U.) for high
pressure sensor
Check thermistor for indoor unit
and outdoor unit inlet air temp.
Check electrical system and
refrigerant system
Check condition of connector
CN100 on O.U.
Check connection.
Replace solenoid valve (SVA)
if faulty.
Open stop valves
Replace high pressure sensor
if faulty.
Replace inlet air thermistor if
faulty.
Correctly connect them
Repair connector for O.U. or
expansion valve.
Replace it if faulty.