a duplex) will start. If vacuum continues to fall,
additional pumps will start to help the system
keep up with the demand as it is needed.
A “Lag Alarm” (if enabled) occurs when the
last available pump starts. If the lag alarm is
activated, the system will emit an audible alarm
as well as a visual alarm on the control panel.
See section 4B.5 for details on adjusting the
lag vacuum switch. Refer to the wiring diagram
supplied with the system for the correct vacuum
switch settings.
On the initial system start-up, when the system
vacuum level is below the set point of the vacuum
control switches, pump 1 will start immediately.
After a 7 second delay, the next pump will start,
followed by the next pump until all pumps have
started. The time delay prevents high inrush
current after a power failure or emergency
power switch over. During this initial system
start-up, the lag alarm (if enabled) may come on
at this point and is normal. It can be reset once
the system reaches its normal operating vacuum
and opens the lag vacuum switch.
When the system satis
fi
es the maximum vacuum
switch setting, the last pump to come on will go
into Purge Mode. If the pumps don’t satisfy the
vacuum setting, they will continue to run for as
long as the pump alternation time is set. Once
the pump alternation time is reached, the lead
pump will go into Purge Mode regardless of the
current vacuum level.
Figure 4B.3 Potentiometer Run Timer Settings (Increments)
Lubricated Rotary Vane Laboratory Vacuum Systems
4107 9021 88.01
4B-2
