Linear Expansion Valve - Mitsubishi Electric PUHZ-P200YKA.UK Service Manual

Linear expansion valve
(1) Operation summary of the linear expansion valve
• Linear expansion valve opens/closes through stepping motor after receiving the pulse signal from the outdoor controller cir-
cuit board.
• Valve position can be changed in proportion to the number of pulse signal.
<Connection between the outdoor controller board and the linear expansion valve>
LEV
3
2
M
5
1
4
6
<Output pulse signal and the valve operation>
Output
(Phase)
1 2 3
[1
ON ON OFF
[2
OFF ON ON
OFF OFF OFF
[3
[4 OFF OFF OFF
(2) Linear expansion valve operation
Close
A
B
Extra tightening (about 32 pulse)
OCH582B
Output
5 6 7 8
4
OFF OFF OFF ON
OFF
ON OFF OFF OFF OFF
ON ON ON OFF OFF
OFF ON ON ON
OFF
C
Open
500 pulse
Opening a valve
all the way
Pulse number
Gray
Orange
[4
[3
Yellow
[2
Black
[1
Connector LEV-A
LEV-B
LEV-C
Opening a valve : 8 → 7 → 6 → 5 → 4 → 3 → 2 → 1 → 8
Closing a valve : 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 1
The output pulse shifts in above order.
· When linear expansion valve operation stops, all output phases
become OFF.
· When the power is turned on, 700 pulse closing valve signal will
be sent till it goes to point in order to define the valve position.
A
(The pulse signal is being sent for about 20 seconds.)
When the valve moves smoothly, there is no sound or vibration
occurring from the linear expansion valve : however, when the
pulse number moves from
more sound can be heard.
N o sound is heard when the pulse number moves from
case coil is burnt out or motor is locked by open-phase.
· Sound can be detected by placing the ear against the screw driv-
er handle while putting the screw driver to the linear expansion
valve.
55
Outdoor controller board
12 V DC
1
Drive circuit
[4
2
[3
Red 3
[2
4
[1
5
to or when the valve is locked,
B A
to in
B A