–37–
[6] Troubleshooting of each part
(1) LEV
1) Overview of LEV operation
LEV (electronic expansion valve) receives pulse signals from the outdoor unit main circuit board and drives a valve
by means of a servomotor.
The valve opening angle changes in proportion to the number of pulses.
<Outdoor controller board and LEV>
<Pulse signal output and valve operation>
The output pulses change in the following order:
Valve closing 1
→
2
→
3
→
4
→
1
Valve opening 4
→
3
→
2
→
1
→
4
*1. When the LEV opening angle is not changed, all output
phases turn OFF.
2. When the output misses a phase or remains ON, the mo-
tor cannot rotate smoothly and makes a clacking sound
and vibrates.
White Red Orange
Blue
Brown
Yellow
Brown
Red
Blue
Yellow
White
Connector
Outdoor controller board CN40
Drive circuit
Output (phase)
No.
ø1
ø2
ø3
ø4
Output state
1
2
3
4
ON
OFF
OFF
ON
ON
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
OFF
ON
ON
LEV opening and closing operations
*
When the power is turned on, to register the valve posi-
tion, a 2200 pulses valve close signal is output and is al-
ways set to point
A
.
If the valve moves smoothly, the LEV will not generate a sound
or vibration, but at
E
→
A
and when the valve is locked, a
sound louder than the sound generated by missing phase,
etc. will be generated.
*
Generation of sound can be checked by placing the tip of
a screwdriver against the valve and your ear against the
handle.
V
alv
e opening angle (flo
w)
Valve closing
Valve opening
Increased throttling region (80 - 100 pulses)
Full open
2000 pulses
Pulse count
D
C
A
E
B
