Hitachi Set Free mini-HNRQ1 Series, Service Manual

Page: 104 / 187

97
Alarm
Code
47
Activation of Low Pressure Decrease Protection
● The alarm code is flashed on the 7-segment display of the outdoor unit.
● The alarm code is displayed on the wired controller of the indoor unit.
★ If the low pressure (Ps) of the compressor is less than 0.09 MPa for 12 minutes, the compressor stops. The
operation automatically restarts after three minutes. If this occurs again twice in the next 60 minutes, this
alarm code is displayed.
O.U: outdoor unit; I.U. PCB: indoor unit PCB
Cause Check Item
Action
(Turn OFF Main Switch)
Event
Check for continuity
after temperature of
outdoor fan motor
decreases.
Faulty
Internal
Thermostat
Replace outdoor fan
motor.
Failure
Measure resistance
with a tester.
Tighten or replace
connector.
Contact
Failure
Check connection. Connect it correctly.
Incorrect
Connection
Excessively
Decreasing
Low Pressure
Internal
Thermostat for
Outdoor Fan
is Activated
in Heating
Operation
Measure coil resistance
and insulation resistance.
Replace outdoor fan
motor if faulty.
Faulty Outdoor Fan Motor
Check charged ref.
volume or check for
leakage.
Repair leakage and
correctly charge ref..
Shortage of Refrigerant
Check electrical system
and ref. system.
Correctly connect
indoor unit and
outdoor unit.
Incorrect Connection
between Indoor Unit and
Outdoor Unit
Check connector
for O.U. PCB.
Replace pressure
sensor if faulty.
Abnormal High
Pressure Sensor
Check stop valve. Open stop valve. Closed Stop Valve
Check Td thermistors
for compressors and
measure Td thermistor
resistance.
Repair or replace
Td thermistor.
Electronic Expansion Valve
Closed by Disconnecting
Td Thermistor
Check connector for
O.U./I.U. PCB.
Repair connector for O.U.
/I.U. PCB or expansion
valve. Replace it if faulty.
Locked Electronic Expansion
Valve for O.U/I.U. (Fully Closed)
TROUBLESHOOTING