Section II - Description
8 Quincy Compressor-QSI
®
Capacity Control System
As the motor starts driving the compressor rotors, air is
exceeds the set point of the pilot valve (normally 110
PSIG), the valve opens and passes a controlled volume of
NOTICE!
Other pressures are available optionally.
The air forces a piston to move within the cylinder,
run, matching air demand with air delivery by constantly
regulates compressor capacity between 100% and nearly
When maximum pressure (typically 10 PSIG above
normal full load pressure) has been obtained in the air
pressure switch located in the control panel sends a signal
to the control and the solenoid valve opens, venting the
time, control air from the reservoir check valve is directed
inlet valve is held in a closed position preventing the
intake of air into the compressor and serving as a check
Auto/Dual (Standard)
in the Continuous Run position, the compressor operates
maximum system pressure is reached, the pressure switch
compressor continues to run unloaded, no air is com-
When the Auto Dual mode is selected, the compressor
will also perform as above; however, a solid state timer is
the timer reaches the end of its delay period, the compres-
sor will automatically shut down and assume a “standby”
switch contacts close, restarting the compressor automati-
During the unloaded/timing mode, if plant pressure
should drop causing the pressure switch contacts to close,
the compressor will continue to operate, resetting the