Linear Expansion Valve; Operation Summary Of The Linear Expansion Valve; Output Pulse Signal And The Valve Operation; Linear Expansion Valve Operation - Mitsubishi Electric SUZ-KA24NAHZ 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 outdoor 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
ø1
ON ON OFF
ø2
OFF ON ON
ø3
OFF OFF OFF
ø4
OFF OFF OFF

(2) Linear expansion valve operation

Close
A
B
Extra tightening (about 32 pulse)
OCH754A
(KA24)
Output
5 6 7 8
4
OFF OFF OFF OFF ON
OFF OFF OFF OFF
ON
ON ON ON OFF OFF
OFF ON ON
OFF ON
C
Open
500 pulse
Opening a valve
all the way
Pulse number
Red
ø4
Blue
ø3
Orange
Yellow
ø2
White
ø1
Connector LEV-A
LEV-B
The output pulse shifts in the following order.
Opening a valve: 8 → 7 → 6 →5 → 4 → 3 → 2 → 1 → 8
Closing a valve: 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 1
• 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
position.
(The pulse signal is being sent for about 20 seconds.)
• When the valve moves smoothly, there is no sound or vibra-
tion occurring from the linear expansion valve; however, when
the pulse number moves from
locked, sound can be heard than normal situation.
No sound is heard when the pulse number moves from
in case coil is burn 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.
52
Outdoor controller board
12 V DC
1
Drive circuit
ø4
2
ø3
3
ø2
4
ø1
5
point in order to define the valve
A
to or when the valve is
B A
to
B A