Changing Target Pressures
The time the system is allotted to change the target
pressure is known as the Pressure Change Time (PC). This
is a value that is adjustable in the system settings screen.
See the Quick Setup Manual.
If the X8I is able to complete the transition in less time
than is allotted without threatening energy efficiency
then PC will be automatically shortened.
An aggressively short time setting will compromise
energy efficiency.
PRESSURE SCHEDULE
The X8I is equipped with a real-time clock feature
and pressure schedule functionality. The pressure
schedule function can be used to provide enhanced
system automation.
The pressure schedule consists of 28 individual settings
that instruct the system to change from one table to
another, or put the system into standby mode dependent
on the time of day and the day of the week. The pressure
schedule will cycle from 00:00 hours Monday (day #1) to
23:59 hours on Sunday (day #7) each calendar week.
The pressure schedule has the capability of changing
tables based on the time of day, once each day, or once
each day except weekends. Please see the Quick Setup
Manual for detailed information on how to configure the
pressure schedule.
The Prefill feature provides a controlled and energy
efficient method of increasing pressure to normal
operating levels at system start. This feature avoids the
inefficient potential for all available system compressors
to start and load before pressure reaches the normal
operating level.
C
At system start (manual start or automated start from
standby) the X8I will only load compressors that have
been pre-determined for prefill operation, for a pre-set
period of time. The prefill time (PT) can be adjusted to suit
system characteristics. The aim is to increase pressure to
normal operational levels, using only the pre-determined
compressors, prior to the prefill time expiring.
If normal operational pressure is reached prior to the
set prefill time, the prefill function will automatically
cease and normal operational control begin. If normal
operational pressure is not reached by the end of
the prefill time the P4 will utilize as many available
compressors as required to achieve normal operational
pressure as quickly as possible. Normal operational
control will then begin.
Three prefill modes are available. 'Backup' and 'Standard'
modes require compressor pre-selection and function in
the same way; differing only in response to a failure, or
loss, of a prefill compressor. Automatic mode requires no
compressor pre-selection.
Backup Mode: Compressor(s) can be pre-selected
as 'Primary Prefill' compressor(s) or 'Backup Prefill'
compressor(s). If a primary prefill compressor experiences
a shutdown, or is stopped, a pre-defined backup
compressor replaces it and prefill continues.
Standard Mode: If one or more of the pre-
defined prefill compressors experiences a shutdown, or
is stopped, the prefill function is cancelled and normal
operation begins.
A
Automatic Mode: No Prefill compressor
selection is necessary; any selection set is ignored. The
management unit automatically selects compressor(s)
dynamically to achieve pressure in accordance with
the set Prefill time. If a compressor is stopped, or shuts
down, it is automatically substituted with an alternative
compressor.
To manually skip Prefill mode, press and hold Start
for several seconds.
Insufficient Capacity Alarm
The X8I is equipped with a dedicated 'Insufficient
Capacity' Advisory Alarm (Warning) indication.
This indication will illuminate if all available compressors
are loaded and system pressure is continuing to decrease.
The indication will generally occur prior to any set low
pressure Alarm (Warning) and is intended to provide an
advanced warning of a potential 'Low Pressure' situation.
17