Hitachi FSXN Series Service Manual page 222

8 Troubleshooting
43
Alarm code
• The RUN indicator flashes and the ALARM indication is displayed on the remote control switch.
• The unit no., the alarm code and the unit code are alternatively displayed in the temperature setting section and the unit
no. and alarm code are displayed on the outdoor unit's PCB1 display.
* This alarm is indicated when the compression ratio, Ɛ = ((Pd + 0.1) / (Ps + 0.06)) is calculated from the discharge
pressure (Pd MPa) and the suction pressure (Ps MPa) and the less than condition Ɛ < 1.8 occurs three times in one
hour.
Does the inverter operate?
Yes
Does the compressor operate?
Yes
Is the reversing valve spindle
mounted at middle position?
No
Are the high-pressure sensor and
the low-pressure sensor normal?
Yes
Is there a leak in the Solenoid
Valve for Hot Gas Bypass (SVA)?
No
Check if the intake air temperature is
too low at the indoor or outdoor units.
Phenomenon
Inverter is not Functioning
Compressor is not Operating
Valve Stoppage at Middle
Position of Reversing Valve
Excessively
Low Compression
Abnormality of High or Low
Ratio
Pressure Sensor
Excessively Low Indoor
Intake Air Temperature
Leakage from Solenoid
Valve (SVA)
216
SMGB0065 rev. 1 - 12/2010
Activation of the low compression ratio protection device.
No
No
Yes
No
Yes
Cause
PCB1: Control PCB in Outdoor Unit
Check the inverter.
Check the compressor and
power cable.
Replace the reversing valve if faulty.
Replace the high-pressure sensor
or the low-pressure sensor if faulty.
Replace the Solenoid Valve
(SVA) if faulty.
Check Item
Check inverter.
Check compressor.
Measure suction pipe
temp. of reversing valve.
Check connector for
PCB1, power source
and pressure indication.
Check indoor unit and
outdoor unit air temp.
thermistor.
Check Solenoid Valve.
Action
(Turn OFF Main Switch)
Repair faulty part.
Replace comp. if faulty.
Replace reversing valve
if faulty.
Replace sensor if faulty.
Replace thermistor
if faulty.
Replace SVA if leaking.