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when the unit is economizing and bringing in large
quantities of outside air.
Space Static Pressure Control with
Statitrac™
Statitrac™ is an option. Space static pressure control
operation will become active when the supply fan is On and
proven, the outdoor air damper position is greater than the
relief enable position setpoint and a valid space static
pressure value is greater than the active space static
pressure setpoint plus half the deadband.
When the activation conditions have been met, the unit will
start the relief fan and control relief damper and fan speed
to maintain the space static pressure setpoint. Once the
relief fan operation is proven, the fan will modulate to track
the relief damper position.
Space pressure control operation terminates when the
relief damper is closed and the space static pressure is
below setpoint minus half the deadband, or space static
pressure is within deadband for 30 minutes.
Space Static Pressure Control without
Statitrac™
If Statitrac™ is not installed, or the space static pressure
sensor has failed, space static pressure control without
Statitrac
TM
becomes active. The relief damper will track to
the outdoor air damper position and the relief fan speed will
track to the relief damper position when the supply fan is
proven On and the outdoor air damper position is greater
than the relief enable position setpoint.
Space static pressure control operation will be terminated
whenever any of the activation conditions are not true,
when the outdoor air damper is fully closed or when the
outdoor air damper is less than the relief enable point
minus 10%.
If the relief fan or damper is in failure, the relief fan will be
commanded Off and the relief damper will be commanded
Closed.
Discharge Air Temperature
Control
Discharge Air Temperature Control uses available heating
and cooling capacity to deliver the required temperature at
the discharge of the unit. A discharge air temperature
sensor is required for operation.
In cooling modes, the control uses cooling sources to
deliver air temperature as required by the Discharge Air
Cooling Setpoint. In heating modes, the control uses heat
sources to deliver air temperature as required by the
Discharge Air Heating Setpoint. Primary heat is never used
in conjunction with mechanical cooling.
Multi Zone-VAV and Constant
Volume - Discharge Temperature
Units
These unit types provide Discharge Air Temperature
Control in all heat, cool, and occupancy modes of
operation. The typical operating mode is Cooling delivering
conditioned air to multiple zones of a building. Multi Zone-
VAV units have duct work to supply VAV terminal units. The
VAV units modulate to control space comfort.
These units also change over to provide heat (when
installed). A building automation system or VAV Box Relay
Output can be used when the heat source requires full
airflow. See Heat Types for more information. A valid space
temperature input must be provided to perform heating
modes such as Daytime Warm Up and Morning Warm Up
(when enabled).
Supply Air Tempering
Supply Air Tempering is a function of discharge air control
Cool mode when DX cooling is off and the outdoor air
damper is at minimum position. This function is typically
required when outdoor air intake percentage is high and
the outdoor air temperature is low. If discharge air
temperature falls below the Discharge Air Cooling Setpoint,
the control will temper (warm up) the discharge air by
initiating heating capacity. Cool – Tempering is displayed
on the user interface Operating Mode screen when this
function is active. The control will transition back to normal
cooling when heat capacity is no longer required. Supply
Air Tempering is disabled by default.
Multi Zone-VAV equipment allows supply air tempering
when equipped with Modulating Gas, Ultra Modulating
Gas, and SCR Electric Heat. Constant Volume – Discharge
Air Temperature equipment allow all forms of heating to
provide supply air tempering.
Changeover Input
Multi Zone-VAV and Constant Volume Discharge
Temperature units configured with heat include a binary
Changeover Input. An open input requests discharge air
cooling operation. A closed input will change over to
discharge air heating. This local input is arbitrated with
building management Heat Cool Mode Request commands
to determine the active mode of operation.
VAV Box Relay Output
This binary output is provided by the controller to be
optionally wired to VAV units in a Multi Zone-VAV system to
coordinate system changeover to full airflow heating. The
binary output is de-energized when the controller is
operating in cooling modes. The binary output energizes
when the heat type installed requires full airflow. See
Maximum Heat for more details.
Summary of Contents for IntelliPak with Symbio 800
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