Trane Symbio 210 Installation, Operation And Maintenance Manual page 37

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Ventilation Setup
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Space CO
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Flow Setpoints Setup
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BAS-SVX091A-EN
Note: The flow offset is calculated only for two-point balancing, which requires reading both the
maximum and minimum airflows during balancing. Two-point balancing ensures greater
accuracy over the entire range of air valve operation.
Airflow Gain: The airflow 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 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.
Ventilation Standby Setpoint: During the occupied standby mode, this setpoint is the active
setpoint for ventilation.
Setup
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Space CO Low Limit: The controller adjusts the ventilation setpoint based on the current CO2
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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 High Limit: The controller adjusts the ventilation setpoint based on the current CO2
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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.
Airflow Setpoint Minimum: Although the UCM will read flow down to 5% of cataloged, the range of
MIN FLOW settings is 0% or 10% to 100% of cataloged. The UCM will not drive its flow below this
minimum flow value under normal operating conditions while in the cool mode. Cool mode occurs
when cool air is in the supply duct. The entry in this field must be less than or equal to the entry in
the Airflow Setpoint Maximum field.
Airflow Setpoint Maximum: This range is 10% to 100% of the cataloged unit CFM size. Cooling
and heating flow can be edited to zero.The UCM will not drive its flow above this maximum flow
value under normal operating conditions while in the Cool mode. Cool mode occurs when cool air is
in the supply duct. The entry in this field must be greater than or equal to the entry in any of the
Minimum fields.
Standby Minimum Airflow: Occupied standby mode is used to reduce the heating and cooling
demands during the occupied hours when the space is temporarily unoccupied. For example, it can
be activated for a classroom currently not in use. Standby Minimum is the minimum amount of
airflow desired during this mode.
Airflow Setpoint Minimum Standby Heat: Occupied standby mode is used to reduce the heating
and cooling demands during the occupied hours when the space is temporarily unoccupied. For
example, it can be activated for a classroom currently not in use. Airflow Setpoint Minimum Standby
Heating is the minimum amount of airflow desired when in the heat mode during this mode.
Airflow Setpoint Minimum Heat: The UCM will not drive its position/flow below this value under
normal operating conditions while in the HEAT mode (warm air in the supply duct) or while it is using
local heat.
Airflow Setpoint Maximum Heat: The controller enters maximum flow heat on receipt of a
communicated command and remains in Airflow Setpoint Maximum Heat until the command
changes. The controller maintains the flow rate at the heating maximum airflow. This is normally
used with a rooftop unit with staged heat that needs a Max constant volume of air movement to keep
the heat exchanger from overheating and tripping the heat in the rooftop unit tripping on a high limit
safety.
Airflow Setpoint Minimum Local Heat: If the Min Local Heat flow is enabled, then this Minimum
Local Heat setpoint is used to determine the minimum position/flow instead of the Airflow Setpoint
Controller Points and Parameters
37