Mitsubishi Electric CAHV-R450YA-HPB Service Manual page 153

[ X Troubleshooting ]
LEV
-4- LEV
1. General descriptions of the operation of the LEV in the main circuit
LEV1 is driven by the pulse signal from the circuit board and is controlled by a stepping motor.
The valve opening changes according to the number of pulses
1) Control board and LEV
LEV
Blue
4
Brown
6
M
Yellow
2
1
White Orange
Note. The connector numbers on the intermediate connector and the connector on the control board differ. Check the color of the lead wire
to judge the number.
2) Pulse signal output and valve operation
Output
(phase)
number
1
1 ON
2 ON
3 OFF
4 OFF
3) LEV valve closing and opening operation
Valve closed
A
E
B
Extra closure range (80 - 120 pulses)
HWE22020
4
3
2
1
Output state
2 3
OFF OFF
ON OFF
ON ON
OFF ON
D
C
Valve open
Fully open
2000/3000 pulses
Pulses
Red
Blue
Orange
Yellow
White
Connector CNLVA/CNLVB
Output pulses change in the following orders when the
Valve is closed; 1
4
Valve is open;
ON
*1. When the LEV opening angle does not change,
OFF
all the output phases will be off.
OFF
*2. When the output is open phase or remains ON,
ON
the motor cannot run smoothly, and rattles and vibrates.
*Upon power on, a 2200 pulse(LEV1)/3200 pulse(LEV3) signal is sent to the LEV to
determine the valve position and bring the valve to the position indicated by " A "
in the diagram
When the valve operates smoothly, no sound from LEV or no vibration
occurs, however, when the pulses change from E to A in the chart or
the valve is locked, a big sound occurs.
*Whether a sound is generated or not can be determined by
holding a screwdriver against it, then placing your ear against the handle.
*If liquid refrigerant is present in the LEV, it may make the operating sound
of the LEV difficult to detect.
- 144 -
Outdoor control board
DC12V
6
Drive circuit
4
4
3
3
2
2
1
1
2 3 4 1
4 3 2 1 4
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