General Overview On Lev Operation (Hydro Unit) - Mitsubishi Electric PUHY-M200YNW-A1 Service Handbook

[8-8 Troubleshooting LEV, FCV Problems ]
8-8-2

General Overview on LEV Operation (Hydro unit)

LEV operation
Hydro unit LEV1 (linear expansion valves) is driven by the pulse signal from the control board and are controlled by a stepping
motor.
(1) Hydro unit LEV
The valve opening changes according to the number of pulses.
1) Control boards and the LEV (Hydro unit LEV1)
LEV
Blue
4
Red
6
M
Yellow
2
5
1
White Orange
2) Pulse signal output and valve operation
Output
(phase)
number
1
1 ON
2 ON
3 OFF
4 OFF
BS_08_E
ø4
ø3
ø2
ø1
Output state
2 3 4
OFF OFF ON
ON OFF OFF
ON ON OFF
OFF ON ON
Control board
6
Brown
5
Blue
4
Orange
3
Yellow
2
1
White
Output pulses change in the following orders when the
Valve is closed; 1 2
Valve is open; 4 3
*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.
DC12V
Drive circuit
ø4
ø3
ø2
ø1
3 4 1
2 1 4
chapter 8 -
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