Quincy Compressor QSI Series Instruction Manual page 11

Auto/Demand (Optional)
The QSI compressor with Auto/Demand controls accom-
modates external control signals from an optional Quincy
Demand-A-Matic multiple compressor controller.
With the selector switch in the Local mode, the compres-
sor will operate exactly as described in the previously
mentioned Auto Dual description.
In the Remote mode, the compressor's control panel
is bypassed in favor of the Demand-A-Matic multiple
compressor controller. The compressor will start, build
air, unload and shutdown on time delay as determined by
the Demand-A-Matic controller. With slight modifica-
tions, a compressor equipped with Auto Dual controls
may be converted to Auto/Demand control. Contact your
authorized Quincy Distributor.
Lead/Lag (Optional, two machines only)
This option allows one of two different pressure control
settings to be chosen for a given machine. If the demand
is greater than one unit's capability, the second com-
pressor will automatically turn itself on until the excess
demand has been satisfied. Again, working with the stan-
dard Auto-Dual control, the second machine would time
out and turn itself off after the demand dropped.
Load/No Load (Optional)
In the Load/No Load mode, the compressor does not
modulate the inlet valve. The valve is either fully open
or it is closed. If systems demands include regular peri-
ods of air usage at less than full load, a large compressed
air storage capability is required with this type of control.
Without adequate storage, rapid cycling may occur. This
will cause wide system pressure fluctuations that may af-
fect the performance of equipment using the compressed
air. Load/No Load works with Auto-Dual control to
turn the compressor off during extended periods of no
demand.
Never assume it is safe to work on a compressor
because it is not operating. It may be in standby
mode and could restart at any time. Follow all
safety instructions in the "Preparing for Mainte-
nance or Service" chapter.
Quincy Compressor-QSI
®
Section II - Description
WARNING!
9