Emerson Vission 20/20 Operation And Service Manual page 64

Section 8 • Timers
Low Oil Pressure Safety Bypass:
• This is the length of time in which the normal Low
(Run) Oil Pressure setpoints will be adjusted by the
values of the Pre-lube Oil Pressure setpoints. After
the timer has expired, the normal Low Oil Pressure
setpoints become active.
Prelube Oil Pressure Monitor Time:
• The Prelube Oil Pressure Monitor time defi nes timer
to monitor raise in prelube oil pressure against pre-
lube oil pressure alarm settings. If prelube oil pres-
sure is unable to raise by oil pressure alarm settings
in Prelube oil pressure monitor time then it restarts
oil pump.
Prelube Oil Pressure Monitor Trials:
• The Prelube oil pressure monitor trials defi nes
maximum number of retries to monitor prelube oil
pressure.
Prelube Oil Pressure Safety Changeover:
• After compressor starts, drop in prelube oil pressure
is monitored for prelube oil pressure safety change-
over time. If prelube oil pressure drops with in pre-
lube oil pressure safety changeover time then com-
pressor trips on prelube oil pressure trip.
High Filter Differential Pressure Safety Changeover:
• This timer bypasses the High Filter Differential Run
Pressure safety settings when the compressor starts.
It defi nes how long the High Filter Differential Start
Pressure setpoints will be active after the compres-
sor starts. After the timer has expired, then the High
Filter Differential Run Pressure safety setpoints will be
active.
Oil Separator Level #1 Safety Trip Delay:
• This timer bypasses the low oil level switch for mo-
mentary drops in the oil level. This timer activates
when the low oil level switch opens, and deactivates
when the switch closes. If the switch is still open af-
ter the timer has timed out, the compressor will be
shut down and a trip message will be displayed. This
timer is available if the unit is equipped with a low oil
separator fl oat switch (the oil level switch is standard
on all liquid injection units and optional on all others).
Oil Separator Level #2 Safety Trip Delay:
• This timer bypasses the low oil level switch for mo-
mentary drops in the oil level. This timer activates
when the low oil level switch opens, and deactivates
when the switch closes. If the switch is still open af-
ter the timer has timed out, the compressor will be
shut down and a trip message will be displayed. This
timer is available if the unit is equipped with a low oil
separator fl oat switch (the oil level switch is standard
on all liquid injection units and optional on all others).
8 – 2
Low Oil Separator Temperature Safety Changeover:
• This timer allows Low Oil Separator Start Temperature
safety setpoint to protect the compressor against
cold oil during starting. After the timer has expired,
the Low Oil Separator Run Temperature is then active.
Low Oil Injection Safety Bypass:
• This timer bypasses the Low Oil Injection Temperature
Safety setpoint during start-up, to allow any cold oil in
the oil lines and fi lter to pass. After the timer expires,
the Low Oil Injection Temperature safety is active.
Reference Figure 8-2.
Max Restart After Power Failure:
• This timer forces the compressor to wait for the set
time period after a power failure and the panels re-
starts before it can be started automatically. By stag-
gering the time settings of this timer between other
compressor panels, the compressors can be allowed
to start automatically, one at a time, after a power
failure. This will prevent excessive load demand on
the power system that could occur if all of the com-
pressor equipment were to start at the same time.
The Power-up Auto Re-Start [x]Enable option must
be selected on the Confi guration screen for this op-
tion to be active.
Hot Starts per Hour:
• This counter counts compressor starts. After every
start, a one-hour timer is reset and starts timing. If
the timer times out, the hot starts counter is reset.
When the counter reaches its preset value, it will not
allow another compressor start until the one-hour
timer times out and resets the counter. The hot starts
counter, therefore, will be reset when the time be-
tween compressor starts total one hour. This coun-
ter allows repetitive compressor starts, but once the
counter has reached its set point, it requires a one-
hour window between compressor starts in order for
the counter to be reset.
True Anti-Recycle Timer:
• Once the compressor turns off, this timer will keep
the compressor off for the setting of the True Anti-
Recycle Timer. This timer is used to prevent short cy-
cling of the compressor.
Accumulative Anti-Recycle Timer:
• This timer forces a specifi ed time between compres-
sor starts. When the compressor starts, the timer
resets and starts timing and accumulates running
time. Once the compressor shuts down, it will not
be allowed to restart for the remainder of time left
on the Accumulative Anti-Recycle Timer. Unlike the
True Anti-Recycle Timer, if the compressor has run
Vission 20/20 • Operation and Service Manual •Vilter/Emerson • 35391SC 2.0