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Unit Startup
Sequence of Operation
NOTICE
Compressor Failure!
Failure to follow instruction below could result in
compressor failure.
Unit must be powered and crankcase heaters
energized at least 8 hours BEFORE compressors are
started.
Stop/Off/Auto
There are a number of reasons the Symbio 800 controller
will have the IntelliPak unit stopped or off. The user
interface home screen displays unit mode of Stopped or
Auto. Stopped is indicated when an override is preventing
operation such as: Local Stop, Emergency Stop or
Equipment Stop input is active. Auto is indicated when in
automatic control but is currently off in modes such as:
Unoccupied, Ventilation Override, Emergency Override or
the like.
When Heat Cool Mode Status is Off, unit operation will be
prevented; whereas, all other modes allow operation.
Power-Up Start Delay
Anytime power is apply to the unit or the controller is reset,
and the unit is able to run, a user adjustable Power-Up
Start Delay setting is enforced to allow staggered starts of
multiple units. The user interface home screen displays
Run Inhibit when active. Power Up Delay Inhibit, with
remaining minutes and seconds, will be displayed on user
interface operating modes screen. Power-Up Start Delay is
also applies to Rapid Restart, or when the controller exits
Ventilation Override or Emergency Override modes.
Normal Unit Starting
When Local Stop, Stop modes, overrides, and diagnostic
shutdowns are removed, the controller will start unit
operation. The supply fan starts and increases to the
minimum Hz setting and must prove On. Unit mode
Running is displayed on the user interface. The supply fan
will run for one minute, with the outdoor air damper closed,
before transitioning into an active heat or cool mode.
Rapid Restart Operation
The purpose of rapid restart is to insure the space
temperature recovers from high heating loads once the unit
has recovered from a power outage. This is accomplished
by utilizing aggressive economizing and/or compressor
staging in a user adjustable amount of time. After a Rapid
Restart event, the unit can subsequently manage the load
using normal capacity control. A typical application is a
data center.
The unit configuration must have Rapid Restart configured
as "Installed" and the Rapid Restart Enable feature setting
62
must be set to "True" to allow this function to operate.
Mechanical cooling (DX) is available for Rapid Restart if the
Outdoor Air Temperature is above the Low Ambient
Lockout setpoint.
After power-up start delay is satisfied, the unit will override
all other forms of time delays (i.e. ICS, VAV Box Stroke
Time, Outdoor Air Damper Stroke Time) and allow the
Supply Fan to start. Once the Supply Fan has proven, the
unit will determine the proper staging sequence by
processing outdoor air temperature and return air
temperature. The unit will generate a Rapid Restart mode
annunciation on the user interface, operating modes
screen.
VOM and Emergency Override have higher priority than
Rapid Restart. If either occur, Rapid Restart will be
terminated and the VOM or Emergency Override will be
performed. Demand limit also has priority over Rapid
Restart.
The unit will terminate Rapid Restart and will de-energize
the VAV Box Relay (if installed), and release to normal unit
control when the Cooling Capacity Status meets or
exceeds the Rapid Restart Capacity Target or when the
Rapid Restart Termination Time expires.
Occupancy
There are many sources and types of occupancy. These
have an effect on the operation of the IntelliPak unit. All
sources are arbitrated (prioritized) into a final occupancy
status.
Sources of Occupancy
•
Occupancy Request is a communicated value from a
Building Automation System (BAS) schedule.
•
Occupancy Input is a local input from the space served
by the equipment. These are typically optional local
time clocks or occupancy sensors. This is a physical
input to the Symbio controller and is field installed.
•
Bypass Timer starts because of a user requested
occupancy override (also known as Occupied Bypass).
The occupant requests temporary occupied comfort
heating or cooling during unoccupied scheduled time
periods. An example of this would be the Timed
Override (TOV) button on the zone sensor. See
Override," p. 63
for more information.
Occupancy Status Definitions
Occupied Operation: The IntelliPak unit is running in a
Normal mode providing temperature and ventilation control
to the normal occupied setpoints and comfort demands of
the occupants.
Unoccupied Operation: The IntelliPak unit is typically shut
down and is not providing temperature control to the
normal occupied setpoints. No ventilation is required or
provided. Temperature control is determined by energy
conservation and building protection thresholds.
"Timed
RT-SVX073A-EN
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