Operation mode
1
→
2
→
3
→
4
→
5
→
6
→
7
→
8
VALVE CLOSE
8
→
7
→
6
→
5
→
4
→
3
→
2
→
1
VALVE OPEN
ON
1
ON
2
OFF
3
OFF
4
5
OFF OFF
6
OFF
7
ON
OFF ON
ON
ON OFF OFF OFF OFF
OFF OFF OFF ON
ON
ON OFF OFF
OFF OFF OFF OFF OFF ON
ON
ON
8
④
③
②
①
④
③
②
①
Connector
Pin No.
12V
0.9V
50ms.
75ms.
200ms.
6-6. Electric expansion valve control circuit
Fig. 6-14
Main P.W.B.
Electric
expansion
valve
Microcomputer
Valve 4
Valve 3
Valve 2
Valve 1
●
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. 6-15 shows logic waveform during the operation of expansion valve.
Table 6-4
Fig. 6-15
CN 15
Pin No.
Lead
wire
Drive status
White
Yellow
Orange
Blue
6-7. Outdoor DC Fan Motor control circuit
This model uses DC Fan Motor which has a controller circuit built in the Motor.
This DC Fan Motor will rotate by control voltage apply to Vsp input. (Voltage range:
(V
(V
1.7 to 7V DC)
Motor will output FG pulse by following this motor revolution.
indoor microcomputer.
This PWM control signal will convert to Vsp voltage by smoothing circuit (R242 & C209)
rotation speed.
DC Fan Motor circuit has to match the Fan Motor revolution with instructed revolution. Such as...
FG feedback: Faster Instruction: Slower ... Decrease pulse width
FG feedback: Slower Instruction: Faster ... Increase pulse width
FG pulse is also used for Fan Motor failure detection.
Microcomputer will monitor FG pulse 30 seconds after start the fan motor. If there is no signal detected,
it will consider that the Fan Motor was malfunction and stop the operation. In this case, LD302 on main
R107 and IC4 are used for Fan Motor over current.
Vsp high : Faster ;
Vsp low
VV
: slower ;
Vsp lower than 1.7V
VV
: stop
P.W.B. will blink 12 times. (Fan Motor lock detected)
FG pulse will feed back to Outdoor microcomputer 53 .
Outdoor microcomputer will output PWM control signal from 24 by following the instruction from
Fan motor will start to rotate when Vsp was proceeding over than 1.7V, and generate FG pulse by
1
24
53
46
45
44
HIC
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