VAV-SVX07F-EN 31
UC400 Controller Points and Parameters
Setup Parameters Screen
Device
Wireless Sensor Enable/Disable: Enables controllers to use wireless sensors in conjunction
with a Wireless Communication Interface (WCI) [enabled by default]. When unchecked, only wired
sensors or wireless sensors using Wireless Receiver Modules (WRM) are allowed.
Space Temperature Source: Th
e drop-down menu is used to select the source of the controllers
space temperature value. Choices are Local Source and BAS.
Occupancy Request Source: Th
e dro
p-down menu is used to select the source of the controllers
Occupancy Request. Choices are Local Source and BAS.
VAV Setup
• Airflow Nominal Status: Nominal flow is the total airflow capacity of the VAV box. Nominal
Flow becomes an active field when Generic is selected in Box Size under Equipment Options
on the Configuration page. Select the CFM nominal flow for the unit. This is normally used when
mounting the tracer UC400 controller on someone else's VAV unit.
• Unit Flo
w G
ain: The flow gain is a multiplier used to calibrate the value reported by the flow
sensor so that the reported airflow matches the actual airflow. Typically, it is not necessary to
change this value. For Trane units, the nominal airflow and unit flow gain are based on unit size
and are not adjustable. The default unit flow gain for generic VAV boxes is 1.0.
• Airflow Measureme
nt Of
fset: The flow offset is used to calibrate the value reported by the
flow sensor so that the reported flow matches the actual flow. The flow offset is determined
during the air balancing process. A test-and-balance professional will use the Tracer TU Air and
Water Balance tool to calculate this value and balance the VAV box. Typically, it is not necessary
to change this value.
Note: Th
e flow offset is calculated only for two-point balancing, which requires reading both
the max
imum and minimum airflows during balancing. Two-point balancing ensures
greater accuracy over the entire range of air valve operation.
• Airflow Gain:
The ai
rflow gain is used to calibrate the value reported by the flow sensor so
that the reported airflow matches the actual airflow. The flow gain is determined during the air
balancing process. A test-and-balance professional will use the TU Air and Water Balance tool
to calculate this value and balance the VAV box. Typically, it is not necessary to change this
value.
Ventilation Setup
• Ventilation Setpoint Local: The Tracer SC BAS uses the ventilation setpoint from all the VAV
boxes to calculate how much outdoor air (OA) the system needs. During the occupied mode,
this setpoint is the active setpoint for ventilation, and should be equal to the ventilation airflow
required at design occupancy of the space.
• Ventil
ation Standby Setpoint: Duri
ng the occupied standby mode, this setpoint is the active
setpoint for ventilation.
Space CO
2
Setup
• Space CO
2
Low Limit: The controller adjusts the ventilation setpoint based on the current
CO2 concentration. When the concentration is less than or equal to this low limit, the zone is
most likely unoccupied and the ventilation setpoint is set equal to Ventilation Standby Setpoint.
When the concentration is between the low and high limits, the ventilation setpoint is adjusted
proportionally between Ventilation Standby Setpoint and Ventilation Setpoint Local.
•Space CO
2
High Limit: The controller adjusts the ventilation setpoint based on the current
CO2 concentration. When the concentration is greater than or equal to this high limit, the zone
is most likely at design occupancy and the ventilation setpoint is set equal to Ventilation
Setpoint Local.
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