Mitsubishi Electric CITY MULTI PUHY-P108 Service Handbook page 335

[ IX Troubleshooting ]
(2) Outdoor LEV (applicable to the PUHY series only)
The valve opening changes according to the number of pulses.
<Connections between the outdoor MAIN board and LEV1 (outdoor expansion valve)>
LEV
4
6
M
2
5
1
3
Pulse signal output and valve operation
Output
(phase)
number 1 2
1 ON OFF OFF OFF OFF OFF ON ON
2 ON ON ON OFF OFF OFF OFF OFF
3 OFF OFF ON ON ON OFF OFF OFF
4 OFF OFF OFF OFF ON ON ON OFF
LEV valve closing and opening operation
Valve closed
Valve open
A
6
5
4
3
2
1
Output state
3 4 5 6 7 8
*When the power is turned on, the valve closing signal of 520 pulses
B
will be output from the indoor board to LEV to fix the valve position.
It must be fixed at point A.
(Pulse signal is output for approximately 17 seconds.)
When the valve operates smoothly, there is no sound from the LEV and no
vibration occurs, but when the valve is locked, noise is generated.
*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 flows inside the LEV, the sound may become smaller.
Fully open: 480 pulses
Pulses
Red
Brown
Blue
Orange
Yellow
White
[Pulse signal output and valve operation]
Output pulses change in the following orders when the
Valve is closed; 1 2
Valve is open; 8 7
*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.
- 326 -
Outdoor MAIN board
DC 12V
6
5
Drive circuit
4 4
3 3
2 2
1 1
3 4 5 6 7 8 1
6 5 4 3 2 1 8