Hitachi Utopia PAS-3HVRG, Service Manual

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TROUBLESHOOTING
(4) Checking Method of Electronic Expansion Valve
(e) By touching the - side of the tester to the L2 terminal
of ACT module and the + side of the tester to the I
terminal of ACT module, measure the resistance.
If all the resistances are greater than 100 k
Ω
, it is
normal.
(f) By touching the + side of the tester to the - terminal
of ACT module and the - side of the tester to the I
terminal of ACT module, measure the resistance.
If all the resistances are less than 100 k
Ω
, it is
normal.
+
-
L2
I
+
-
-
I
+
Indoor Unit Electronic Expansion Valve Outdoor Unit Electronic Expansion Valve
Locked Check for the liquid pipe temperature It is abnormal if the liquid pipe pressure
with during heating operation. does not increase during cooling
Fully Closed It is abnormal if the temperature does operation.
not increase.
Locked It is abnormal under the following It is abnormal if the liquid pipe pressure
with conditions; The temperature of freeze does not increase and the outlet
Slightly Open protection thermistor becomes lower temperature of the expansion valve
than the suction air temperature when decreases after the cooling operation
the unit under checking is stopped and is started.
other units are under cooling operation.
Locked It is abnormal under the following
with conditions; After heating operation for
Fully Open more than 30 min., the discharge gas
temperature of compressor is not 10
o
C
higher than the condensing temperature
and there is no other faults such as
excessive charge of refrigerant, etc.
Unit
Under
Checking
Electronic Expansion Valve
Freeze Protection
Thermistor
Other
Units