Mitsubishi Electric City Multi PLFY Series Technical & Service Manual page 21

8-1-2. Flow control valve
1) Summary of flow control valve (FCV) operation
The FCV is operated by a stepping motor, which operates by receiving a pulse signal from the indoor control board.
The FCV position changes in response to the pulse signal.
Limit signal
(Opening
"0" signal)
Ø1
M
Ø3
Ø2 Ø4
Pulse signal output and valve operation
Output (phase)
number
1
Ø
2
Ø
3
Ø
4
Ø
2) FCV operation
(f)
(c)
OCH717
Flow control valve
Connector
Gray
1
White
2
3 Purple
4
5
Blue
6
Ø4 Green
7
Ø3 Red
8
Orange
Ø2
Yellow
Ø1
Connector (CN8A)
Output status
1 2 3
OFF ON ON
ON ON OFF
ON OFF OFF
OFF OFF ON
(a)
(b)
(d)
(e)
Control board
8
GND
7
6
12V
5
Drive circuit
Ø4
4
Ø3
3
Ø2
2
Ø1
1
The output pulse changes in the following order:
When the valve closes 1 -> 2 -> 3 -> 4 -> 1
4
When the valve opens 4 -> 3 -> 2 -> 1 -> 4
OFF
OFF
ON
ON
(a) Close
(b) Open
(c) Fully open valve (85 pulses)
(d) Fully close valve (770 pulses)
(e) No. of pulses
(f) Valve opening degree
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