Hitachi FS3 Series, Service Manual

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1
TROUBLESHOOTING
93
b. By touching the - side of the tester to the + terminal of
the diode module and the + side of tester to the ~
terminals (3 Nos.) of the diode module, measure the
resistance. If all the resistances are greater than 500 k
W
,
it is normal.
c. By touching the - side of the tester to the - terminal of the
diode module and the + side of tester to the
~
terminals
(3 Nos.) of the diode module, measure the resistance. If
all the resistances are from 5 to 50 k
W
, it is normal.
d. By touching the + side of the tester to the - terminal of
the diode module and the - side of tester to the
~
terminals (3 Nos.) of the diode module, measure the
resistance. If all the resistances are greater than 500 k
W
,
it is normal.
b)
c)
d)
n
Checking Method of Electronic Expansion Valve
Indoor Unit Electronic Expansion Valve Outdoor Unit Electronic Expansion Valve
Locked with Fully Closed
Check for the liquid pipe temperature during
heating operation.
It is abnormal if the temperature does not
increase.
It is abnormal if the liquid pipe pressure does
not increase during cooling operation.
Locked with Slightly Open
It is abnormal if the liquid pipe pressure does
not increase and the outlet temperature of
the expansion valve decreases after the
cooling operation is started.
Locked with Fully Open
It is abnormal under the following conditions;
The temperature of freeze protection thermistor
becomes lower than the suction air temperature
when the unit under checking is stopped and
other units are under cooling operation.
It is abnormal under the following conditions;
After heating operation for more than 30
min., the discharge gas temperature of
compressor is not 10 °C higher than the
condensing temperature and there is no
other faults such as excessive charge of
refrigerant, etc.
Electronic expansion Valve
Freeze Protection
Thermistor
Unit under
checking
Other
units