Linear Expansion Valve - Mitsubishi Electric PUHZ-P200YHA 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 board.
• Valve position can be changed in proportion to the number of pulse signal.
<Connection between the indoor controller board and the linear expansion valve>
LEV
3
2
M
5
1
6 4
<Output pulse signal and the valve operation>
Output
(Phase)
1 2 3
1
ON ON OFF
2
OFF ON ON
3
OFF
OFF OFF
4
OFF OFF OFF
(2) Linear expansion valve operation
Close
Extra tightning (about 32 pulse)
Output
4 5 6 7 8
OFF OFF OFF OFF ON
ON OFF OFF OFF OFF
ON ON OFF OFF
ON
OFF ON ON ON
OFF
Open
500 pulse
Opening a valve
all the way
Pulse number
4
Orange
3
2
1
Connector LEV-A
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 phase
become OFF.
• When the switch is turned on, 700 pulse closing valve signal will be
sent till it goes to point in order to define the valve position. (The
A
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 to
B
be heard.
No 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 driver
handle while putting the screw driver to the linear expansion valve.
49
Outdoor controller board
DC12V
Gray 1
Drive circuit
3
Red 4
Yellow
5
Black 6
or when the valve is locked, sound can
A
4
3
2
1
to in
B A