Quincy Compressor QSI Series Instruction Manual page 15

Auto/Demand (Optional)
The QSI compressor with Auto/Demand controls
accommodates external control signals from an optional
Quincy Demand-A-Matic multiple compressor controller.
With the selector switch in the Local mode, the
compressor 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
modifications, 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
compressor will automatically turn itself on until the
excess demand has been satisfied. Again, working with
the standard 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
periods 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 affect 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
Maintenance or Service" chapter.
Quincy Compressor-QSI
Section II - Description
WARNING!
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