Mitsubishi Electric PEFV-P72NMHSU-E Technical & Service Manual page 57

LEV
4.
LEV operation
An LEV (Indoor unit: Linear expansion valve), is a stepping-motor-driven valve that operates by receiving the pulse signals
from the indoor and outdoor unit control boards.
1. Indoor LEV
The valve opening changes according to the number of pulses.
(1) Indoor controller board and LEV connection.
(J)
(C)
4
(A)
M 6
(E)
5 2
1
3
(F) (B) (D)
(A) Brown
(B) Red
(C) Blue
(D) Orange
(E) Yellow
(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
HWE1017B
(F) White
(G) Control board
(H) Connection (CN60,CN7V)
(I) Drive circuit
(J) Linear expansion valve
Output state
2 3 4
OFF OFF ON
ON OFF OFF
ON ON OFF
OFF ON ON
D
C
Valve open
Fully open: 2000 pulses
Pulses
(A)
(B)
(C)
(D)
(E)
(F)
(H)
Output pulses change in the following orders when the
Valve is closed; 1
Valve is open; 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.
- 51 - 51
(G)
12VDC
6
5
(I)
4
3
2
1
2 3 4 1
3 2 1 4
GB