16
Output
(Phase)
Output
{
1
1
ON
{
2
ON
{
3
OFF
{
4
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
V
alve position (capacity)
6
5
4
3
2
1
LED
1
T
Symptom
Check points
Operation circuit
failure of the
micro processor.
Disconnect the connector on the controller board,
then connect LED for checking.
Pulse signal will be sent out for 10 seconds as soon as
the main switch is turned on. If there is LED with lights
on or lights off, it means the operation circuit is abnormal.
Countermeasures
Exchange the indoor
controller board at drive
circuit failure.
Linear expansion
valve mechanism
is locked.
Valve doesn't
close completely
(thermistor leak-
ing).
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
outdoor multi controller board operation
monitor. During fan operation, linear
expansion valve is closed completely and if
there are some leaking, detecting tempera-
ture of the thermistor will go lower. If the
detected temperature is much lower than
the temperature 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.
Liquid pipe
thermistor
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 connector.
Exchange the linear
expansion vale.
Exchange the linear
expansion valve.
If large amount of ther-
mistor is leaked,
exchange the linear
expansion valve.
Disconnect the connec-
tor 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 150
'
+10%.
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 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 posi-
tion.
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.
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