Mitsubishi Electric PKFY-WL04NLMU-E.TH Technical & Service Manual page 21

Parts name
▪ Pressure sensor (inner water) PS1
Pressure sensor
▪ Pressure sensor (outlet water) PS2
(Optional parts)
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
9-1-1. Thermistor
<Thermistor characteristic graph>
thermistor (TH21)
Thermistor for
(Room temperature detection)
lower temperature
thermistor (TH22)
(Pipe temperature detection/ inlet)
thermistor (TH23)
(Pipe temperature detection/ outlet)
Thermistor R =15 k" ± 3%
0
Fixed number of B=3480 ± 2%
Rt=15exp { 3480(
273+(t-32)/1.8
30°F 15.8kΩ
50°F 9.6kΩ
70°F 6.0kΩ
80°F 4.8kΩ
90°F 3.9kΩ
100°F 3.2kΩ
9-1-2. 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
Ø
1 OFF
Ø
2 ON
Ø
3 ON
Ø
4 OFF
TCH122
1 1
) }
273
Flow control valve
Connector
1 Gray
White
2
Purple
3
4
5
Blue
6
Ø4
7 Green
Ø3
8 Red
Ø2
Orange
Ø1
Yellow
Connector (CN8A)
Output status
2 3
ON ON OFF
ON OFF OFF
OFF OFF
OFF ON
Checkpoints
PS1
GND(RED)
Vout(Brown)
Vcc(DC5V)(Orange)
50
40
30
20
10
0
-20
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
ON
ON
21 21
PS2
GND(Blue)
Vout(White)
Vcc(DC5V)(Yellow)
Connector
CNSA
(White)
< Thermistor for lower temperature >
0 20 40 60 80
Temperature (°F)
Microprocessor
Connector
CNSB
(Black)
100 120