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Output
(Phase)
Output
ø1
1
ON
ø2
ON
ø3
OFF
ø4
OFF
2
OFF
ON
ON
OFF
3
OFF
OFF
ON
ON
4
ON
OFF
OFF
ON
<Output pulse signal and the valve operation>
➁
Linear expansion valve operation
➂
Trouble shooting
D
A
E
B
C
Open
Extra tightning (80~100pulse)
Pulse number
2000 pulse
Opening a valve
all the way
Close
Valve position (capacity)
6
5
4
3
2
1
LED1kΩ
Symptom
Check points
Operation circuit fail-
ure of the micro
processor.
Disconnect the connector on the controller board, then con-
nect LED for checking.
Pulse signal will be sent out for 10 seconds as soon as the
main switch is turn on. If there is LED with lights on or lights
off, it means the operation circuit is abnormal.
Countermeasures
Exchange the indoor con-
troller board at drive circuit
failure.
Linear expansion
valve mechanism is
locked.
Valve doesn
´t close
completely (thermis-
tor leaking).
Wrong connection of
the connector or
contact failure.
To check the linear expansion valve, operate the indoor unit in
fan mode and at the same time operate other indoor units in
cooling mode, then check the pipe temperature <liquid pipe
temperature> of the indoor unit by the out-
door multi controller board operation moni-
tor. During fan operation, linear expansion
valve is closed completely and if there are
some leaking, detecting temperature of the
thermistor will go lower. If the detected
temperature is much lower than the temper-
ature indicated in the remote controller, it
means the valve is not closed all the way. It is not necessary
to exchange the linear expansion valve, if the leakage is small
and not making any trouble.
Thermistor
(TH21)
Linear
expansion
valve
Motor will idle and make ticking noise when motor is operated
while the linear expansion valve is locked. This ticking sound
is the sign of the abnormality.
Check the color of lead wire and missing terminal of the con-
nector.
Exchange the linear
expansion vale.
Exchange the linear
expansion valve.
If large amount of refriger-
ation is leaked, exchange
the linear expansion valve.
Disconnect the connector
at the controller board,
then check the continuity.
Measure the resistance between the each coil (red-white,
red-orange, brown-yellow, brown-blue) using a tester. It is
normal if the resistance is in the range of
Short or breakage of
the motor coil of the
linear expansion
valve.
Closing a valve : 1 → 2 → 3 → 4 → 1
Opening a valve : 4 → 3 → 2 → 1 → 4
The output pulse shifts in above order.
1. When linear expansion valve operation stops, all output phase
become OFF.
2. At phase interruption or when phase does not shift in order,
motor does not rotate smoothly and motor will locks and vibrates.
When the switch is turned on, 2200 pulse closing valve signal
will be send till it goes to A point in order to define the valve
position.
When the valve move smoothly, there is no noise or vibration
occurring from the linear expansion valve : however, when the
pulse number moves from E to A or when the valve is locked,
more noise can be heard than normal situation.
✻
✻
✻
Noise can be detected by placing the ear against the screw dri-
ver handle while putting the screw driver to the linear expansion
valve.
150Ω
10%.