Hitachi RAS-10FXG - 2.4.9 Removing Drain-Up Mechanism; 2.4.10 Removing Float Switch

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TROUBLESHOOTING
 “RUN” light flickers and “ALARM” is indicated on the remote control switch.
 The unit No., alarm code and the unit code is alternately indicated on the set temperature section,
and the unit No. and alarm code are indicated on the display of the outdoor unit PCB.
 This alarm code is indicated when the pressure sensor voltage decreases lower than 0.1V or
increases higher than 4.9V during running.
Alarm
Code
Abnormality of High Pressure Sensor for Outdoor Unit
Is the connection CN7
of the outdoor unit
PCB1 bad?
Is 12 VDC applied
across #1 and #3 of the
connector CN7 of the
outdoor unit PCB1?
Yes
Yes
Is voltage under
0.1 VDC or over 4.9VDC
across #2 and #3 of the
connector CN7 of the
outdoor unit PCB1?
Clogged Check Joint?
Abnormality of High
Pressure Sensor.
Connect correctly.
PCB1 defective.
Yes
No
No
No
No
Faulty PCB1.
Replace check joint.
Yes
Cause
Check Item
Action
(Turn OFF Main Switch)
Phenomenon
Faulty High
Pressure Sensor
Check output voltage
is correct.
Replace pressure
sensor if faulty.
Fault
Indicated
Pressure Value
is Excessively
High or Low
Check for clogging
of check joint.
Replace check joint.
Malfunction of Pressure
Sensor due to Faulty
Check Joint
Check connections.
Repair wiring and
connections.
Incorrect Connection
Replace PCB and
check operation.
Replace PCB if faulty.Faulty PCB