Mitsubishi Electric CITY MULTI PLFY Series Technical & Service Manual page 20

9-1-2. 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
Ø
1
Ø
2
Ø
3
Ø
4
2) FCV operation
(f)
(c)
TCH123
Flow control valve
Connector
1
2
3
4
5
6
7
8
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
Gray
8
White GND
7
Purple
6
5
Blue
Ø4
Green
4
Ø3
Red
3
Ø2
Orange
2
Ø1
Yellow
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
20
Microprocessor
12V
Drive circuit
Ø4
Ø3
Ø2
Ø1