OC290-25
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
1k
"
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 outdoor multi controller board opera-
tion monitor. During fan operation, linear
expansion valve is closed completely and
if there are some leaking, detecting tem-
perature 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.
Thermistor
(Liquid pipe)
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 thermis-
tor 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 lock 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 moves 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 driver
handle while putting the screw driver to the linear expansion valve.
150
'
10%.
OC290--1.qxp 02.9.26 4:23 PM Page 25
