42
Centrifugal Chillers
D-EIMWC00804-14EN
Figure 22, Vane Control Solenoid Operation
Compressor
Unloader
Cylinder
Floating Piston Linked to Inlet Vanes
Opens Vanes
Closes Vanes
Four-Way Solenoid
Valve Located on
Compressor or
in Lube Box
Piston Drain
#3 Outlet
SB
SA
#1 Inlet
LEGEND
Oil Under Pressure
To Oil
Pump Sump
Section “SB”
De-energized
Section “SA”
De-energized
From Oil
Pump Discharge
Adjustable Needle Valves
Integral With Four-Way
Solenoid Valve
HOLDING
Figure 23, Vane Control Solenoid Operation, Continued
Drain From Piston
#3 Outlet
SB
SA
#1 Intlet
LEGEND
Oil Under Pressure
To Oil
Pump Sump
Section “SB”
Energized
Section “SA”
De-energized
From Oil
Pump Discharge
OPENING
Oil Sump Pressure
Drain From Piston
#3 Outlet
SB
SA
#1 Intlet
To Oil
Pump Sump
Section “SB”
De-energized
Section “SA”
Energized
From Oil
Pump Discharge
CLOSING
Piston Drain
