Mitsubishi Electric PUHY-HP200 Service Handbook page 200

[ IX Troubleshooting ]
-5- LEV
LEV operation
LEV (Indoor unit: Linear expansion valve), LEV1, LEV2a, LEV2b, and LEV4 (Outdoor unit: Linear expansion valve) are step-
ping-motor-driven valves that operate by receiving the pulse signals from the indoor and outdoor unit control boards.
(1) Indoor LEV and Outdoor LEV (LEV2a, LEV2b)
The valve opening changes according to the number of pulses.
1) Indoor and outdoor unit control boards and the LEV (Indoor unit: Linear expansion valve)
LEV
Blue
4
Brown
6
M
Yellow
2
5
1
White Red 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
80 - 100 pulses
HWE08110
4
3
2
1
Output state
2 3
OFF OFF ON
ON OFF OFF
ON ON OFF
OFF ON ON
D
C
Valve open
Fully open: 1400 pulses
Pulses
Intermediate connector
Brown
2
Red
5
Blue
1
Orange
3
Yellow
4
White
6
Output pulses change in the following orders when the
Valve is closed; 1
4
Valve is open;
*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.
- 191 -
Outdoor control board
DC12V
6
5
Drive circuit
4
4
3
3
2
2
1
1
2 3 4 1
4 3 2 1 4
GB