Table of Contents
Advertisement
Available languages
Available languages
3. Latch-type reversing valve control circuit
Main P.W.B.
Electric
expansion
valve
Electric expansion valve is driven by B-12V. Opening of the valve is controlled by feeding power to 1
or 2 phases of the 4-phase coil to switch the polarity of the coil.
The relation between the conducting phase switching direction and open/close direction is as shown
below. When the power is turned on, approx. 0.9 V is applied to CN15 pins 1 to 4 ; when no power
is supplied, approx. 12 V is applied. When the power is reset, expansion valve performs initial
operation for 5 to 10 seconds.During initial operation, measure pins 1 to 4 of CN15 using
multimeter: If no change is found around 0.9 V or 12V, expansion valve or microcomputer is
defective.
Fig. 3-1 shows logic waveform during the operation of expansion valve.
CN 15
Lead
Pin No.
wire
1
2
ON
ON
White
Yellow
OFF
O N
OFF
OFF
Orange
OFF
OFF
Blue
1
2
3
4
5
6
8
7
6
5
4
3
5 0m s.
Fig. 3-1
Table 3-1
Drive status
3
4
5
OF F
OF F
O FF
OF F
ON
ON
OF F
OFF
OF F
O N
ON
ON
OF F
OFF
O FF
ON
7
8
VALVE C LOSE
2
1
VALVE OPEN
7 5m s.
20 0m s.
Fig. 3-2
– 91 –
H C
16
15
14
13
6
7
8
OFF
O N
O FF
OF F
O FF
OF F
O N
ON
1 2V
0 .9V
Hide quick links:
Advertisement
Table of Contents
