Hitachi FS3 Series, Service Manual

Page: 59 / 240

1
TROUBLESHOOTING
51
Alarm Code
44
Activation to Protect System from Excessively High Suction Pressure
n
”RUN” light flickers and ”ALARM” is indicated on the remote control switch.
n
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 compressor is operated under the conditions higher than 0.9 MPa of
suction pressure and its occurrence is more than 3 times including 3 in one hour.
Is there a leak in the solenoid valve
SVA?
Yes
Replace the solenoid valve SVA if
faulty.
No
Is the four-way valve spindle mounted
at the middle position?
Yes
Replace the four-way valve if
faulty.
No
Is the low-presuure sensor good?
No
Replace the low-pressure sensor if
faulty.
Yes
Check if the indoor/outdoor intake air
temperature is too high.
Phenomenon Cause Check Item
Action
(Turn OFF main switch)
Leakage of Solenoid Valve
SVA
Check outlet pipe temp. of
solenoid valve, SVA.
Check connecting wires.
Replace solenoid valve,
SVA if faulty.
Valve Stoppage at Medium
Position of 4-Way Valve
Measure suction gas pipe
temp. of 4-way valve
Replace 4-way valve if
faulty.
Abnormal Suction Pressure
Sensor
Check connectors of PCB
and power source.
Replace sensor if faulty.
Excessively
High Suction
Pressure
Excessively High Indoor Unit
and Outdoor Unit Suction Air
Temperature
Check indoor unit and
outdoor unit suction air temp.
thermistor.
Replace thermistor if
faulty.