Mitsubishi Electric PUZ-HA24NHA1, Service Manual

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55
OCH750A
<Output pulse signal and the valve operation>
(2) Linear expansion valve operation
Open
Extra tightening (about 32 pulse)
Pulse number
500 pulse
Opening a valve
all the way
Close
Valve position (capacity)
A
B
C
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
A
point in order to define the valve
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
B
to
A
or when the valve is
locked, sound can be heard than normal situation.
No sound is heard when the pulse number moves from
B
to
A
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.
LEV
M
1
6
ø4
ø4
ø3
ø2
ø1
1
Red
Blue
Orange
Yellow
White
2
3
4
5
Connector LEV-A
LEV-B
12 V DC
Outdoor controller board
Drive circuit
ø3
ø2
ø1
3
2
5
4
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>
1
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
OFF
ON
OFF
OFF
OFF
ON
ON
OFF
ø1
Output
(Phase)
Output
ø2
ø3
ø4
2 3 4
5 6 7 8
OFF
OFF
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
ON
(HA24)