Subcooling Lev Control; Fan Control; Oil Return Control On Cooling Mode - LG multi V PLUS Service Manual

1.4 subcooling LEV control

Subcooling LEV works with fuzzy rules to maintain the subcooling degree at the outlet of subcooler during
cooling mode
Subcooling degree = Tcondensation -Tliquid
Tliquid : temperature at outlet of subcooler(˚C)
Tcondensation : condensation temperature equivalent to high pressure(˚C)

1.5 Fan control

Main unit's fan motor operates with inverter drive by fuzzy control and sub units°Ø fan motors are all step
motors.
Fan Step
0
1
2
3
4
5
1. Basic control
2.1 Oil return control

2.1.1 Oil return control on cooling mode

Component
Inv Compressor
Sub unit 's
compressor
Fan
Main LEV
4 way valve
Subcooling LEV
Hot gas bypass
valve
Sub unit
Left fan Right fan
Stop Stop
Low Stop
High Stop
Low Low
High Low
High High
Starting
30 Hz
All off
High pressure
0 Hz
Full open
Off
min.
Off
Main unit
Fan frequency
<5 Hz
5 Hz ≤ Frq < 10Hz
10 Hz ≤ Frq < 20Hz
20 Hz ≤ Frq < 30Hz
30 Hz ≤ Frq < 40Hz
Frq ≥ 40Hz
Running
60 Hz
On
High pressure
control
Full open Base pulse
Off
min.
Off
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Function
Ending
30 Hz
Off
control
Off
min.
Off