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Controller Points and Parameters
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Setpoint Limits
Each point has its own min/max, therefore, the following setpoint limits are incorporated in the occupied
setpoint point, standby setpoint point, and unoccupied heat/cool setpoints. After the controller
completes all setpoint calculations, the calculated occupied setpoint is validated against these
configured space setpoint limits:
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These setpoint limits apply only to the occupied and occupied standby, heating and cooling setpoints.
They do not apply to the unoccupied heating and cooling setpoints. When the controller is in the
unoccupied mode, it always uses the unoccupied heating and cooling setpoints. Unit configuration
enables or disables the local (hard-wired) setpoint. This parameter provides additional flexibility to allow
the user to apply communicated, hard wired, or default setpoints without making physical changes to
the unit. Similar to hard-wired setpoints, the effective setpoint value for a communicated setpoint is
determined based on the stored default setpoints, configuration values, and the controller occupancy
mode.
Setup Parameters Screen
Device
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VAV Setup
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Occupied Offset: Setpoints have a range from 0.9°F to 45°F (-17.27°C to 7.22°C). If a zone sensor
thumbwheel setpoint is not being used, this setpoint are added and subtracted from the Space
Temperature Setpoint Default to determine the occupied heating and cooling setpoints.
Standby Offset: Setpoints have a range from 0.9°F to 45°F (-17.27°C to 7.22°C). If a zone sensor
thumbwheel setpoint is not being used, this setpoint are added and subtracted from the Space
Temperature Setpoint Default to determine the standby heating and cooling setpoints.
Space Temperature Setpoint Default: Setpoints have a range from 40.0°F to 115.0°F (4.44°C to
46.11°C). If a zone sensor thumbwheel setpoint is not being used, this setpoint is used as the active
cooling setpoint during occupied times for the UCMs. The cooling setpoint must be greater than or
equal to the heating setpoint plus 2.0°F (1.1°C).
Heating Setpoint High Limit
Heating Setpoint Low Limit
Cooling Setpoint High Limit
Cooling Setpoint Low Limit
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: The drop-down menu is used to select the source of the controllers
space temperature value. Choices are Local Source and BAS.
Occupancy Request Source: The drop-down menu is used to select the source of the controllers
Occupancy Request. Choices are Local Source and BAS.
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 Symbio 500 controller on someone else's VAV unit.
Unit Flow Gain: 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 Measurement Offset: 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.
BAS-SVX091A-EN
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Table of Contents
Troubleshooting
