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

Parts name
Pressure sensor ▪ Pressure sensor (inner water) PS1
(Optional parts) ▪ Pressure sensor (outlet water) PS2
1. Check that the pressure sensor is connected.
2. Check the pressure sensor wiring for breakage.
Pressure 0-1.0 MPa [145 psi] Vout 0.5-4.5 V
0.392 V/ 0.098 MPa [14 psi]
Pressure [MPa] = 0.25 × Vout [V] - 0.125
Pressure [psi] = (0.25 × Vout [V] - 0.125) × 145
8-1-1. Thermistor
<Thermistor characteristic graph>
Room temperature detection thermistor (TH21)
Thermistor for
Pipe temperature detection thermistor/liquid (TH22)
lower temperature
Pipe temperature detection thermistor/gas (TH23)
Thermistor R =15 k" ± 3%
0
Fixed number of B=3480 ± 2%
1
Rt=15exp { 3480(
273+t
0: 15 k"
10: 9.6 k"
20: 6.3 k"
25: 5.4 k"
30: 4.3 k"
40: 3.0 k"
8-1-2. Flow control valve (FCV)
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.
Indoor control board and FCV connection
Limit signal
(Opening
"0" signal)
Ø1
M
Ø3
Ø2 Ø4
Pulse signal output and valve operation
Output (phase)
number
1
1 OFF
Ø
2 ON
Ø
3 ON
Ø
4 OFF
Ø
OCH711
1
) }
273
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
2 3 4
ON ON OFF
ON OFF OFF
OFF OFF ON
OFF ON ON
Check points
PS1
GND(RED)
Vout(Brown)
Vcc(DC5V)(Orange)
< Thermistor for lower temperature >
50
40
30
20
10
0
-20
Control board
8
GND
7
Microcomputer
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
When the valve opens 4 -> 3 -> 2 -> 1 -> 4
20
PS2
GND(Blue)
Connector
Vout(White)
CNSB
Vcc(DC5V)(Yellow)
Connector
(Black)
CNSA
(White)
-10 0 10 20 30 40
Temperature (:)
50