Service manual

21
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 tightening (80~100pulse)
Pulse number
2000 pulse
Opening a valve
all the way
Close
Valve position (capacity)
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 point
A in order to define the valve posi-
tion.
When the valve moves smoothly, there is no noise or vibration
occurring from the linear expansion valves : however, when the
pulse number moves from E to A or when the valve is locked,
more noise can be heard than in a normal situation.
❈ Noise can be detected by placing the ear against the screw
driver handle while putting the screw driver tip to the linear
expansion valve.
6
5
4
3
2
1
LED1k"
Symptom
Check points
Operation circuit fail-
ure of the micro
processor.
Disconnect the connector on the controller board, then con-
nect LED for checking.
When power is turned on, pulse signals will send for 10
seconds. If the LED does not light or keeps lighting even
after the signals stop, that means some failures in the
operation circuit.
Countermeasures
Exchange the indoor con-
troller board at drive circuit
failure.
Linear expansion
valve mechanism is
locked.
Valve doesn't close
completely.
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 is any leaking, detecting temperature
of the thermistor will go lower. If the detect-
ed temperature is much lower than the tem-
perature indicated in the remote controller,
it means the valve is not closed all the way. It is not neces-
sary to exchange the linear expansion valve, if the leakage is
small and not affecting normal operation.
Thermistor
(Liquid pipe)
Linear
expansion
valve
Motor will idle and make a ticking noise when the 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 each coil (white-red, yellow-
brown, orange-red, blue-brown) using a tester. It is normal if
the resistance is in the range of 150Ω ±10%.
Short or breakage of
the motor coil of the
linear expansion
valve.
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