Mitsubishi Electric PU(H)Y-P250YGM-A, Service Handbook

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[
IX
Troubleshooting ]
-5- LEV
LEV operation
The LEV (indoor: linear expansion valve), SLEV1, and LEV1 receive pulse signal from the indoor and outdoor main circuit
boards, and drive the valve by stepping motor.
(1) Indoor unit LEV
The valve opening changes according to the number of pulses.
<Connections between the indoor/outdoor control board and LEV (indoor expansion valve)>
Pulse signal output and valve operation
LEV valve closing and opening operation
LEV
M
Blue
4
6
2
3
5
1
White Red Orange
Brown
Yellow
4
3
2
1
4
3
2
1
2
5
1
3
4
6
6
5
4
3
2
1
Brown
Blue
Red
Orange
Yellow
White
Intermediate connector
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.
Connector
Indoor unit connector CN60
Control board CNLV1,CNLV2
Drive circuit
DC 12V
Control board
Output state Output
(phase)
number
1 2 3 4
1 ON OFF OFF ON
2 ON ON OFF OFF
3 OFF ON ON OFF
4 OFF OFF ON ON
Output pulses change in the following orders when the
Valve is closed; 1 2 3 4 1
Valve is open; 4 3 2 1 4
*1. When the LEV opening angle does not change,
all the output phases will be off.
*2. When the output is open phase or remains ON,
the motor cannot run smoothly, and rattles and vibrates.
*When the power is turned on, the valve closing signal of 2200 pulses
will be output from the indoor board to LEV to fix the valve position.
It must be fixed at point A.
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.
Valve opening (refrigerant flow rate)
Valve closed
Valve open
E
B
80 - 100 pulses
Pulses
Fully open: 2000 pulses
A
C
D