Mitsubishi Electric Mr.Slim PKFY-P32VGM, Technical & Service Manual

Page: 13 / 22

13
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>
2
Linear expansion valve operation
3
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
Symptom Check points
Operation circuit
failure 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 turned 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 operation
monitor. During fan operation, linear expan-
sion 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 tem-
perature 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 con-
nector.
Exchange the linear expan-
sion vale.
Exchange the linear expan-
sion 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 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
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 driv-
er handle while putting the screw driver to the linear expansion
valve.
OC179B