Trane Tracer Uc page 42

Tracer™ UC400 Controller Operations
Ventilation Setup
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Space CO
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Flow Setpoints Setup
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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.
Ventilation Standby Setpoint: During the unoccupied mode, this setpoint is the active
setpoint for ventilation.
Setup
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Space CO Low Limit: The controller adjusts the ventilation setpoint only when the CO
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concentration falls within the high and low limits. When the CO
low limit, this indicates that the zone is most likely unoccupied and that a minimum of
ventilation air is required to ventilate the zone.
Space CO High Limit: The controller adjusts the ventilation setpoint only when the CO
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concentration falls within the high and low limits. When the CO
high limit, this indicates that the zone is most likely at its maximum design occupancy and that
a maximum of ventilation air is required to ventilate the zone.
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 the Cooling Minimum field
must be less than or equal to the entry in the 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 for Maximum Flow 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 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 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 the Min
Local Heat flow is used to determine the minimum position/flow instead of the Min Heating
Flow when local heat is on. The entry for Min Heating Flow must be less than or equal to the
entry for the maximum.
concentration falls below the
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concentration rises above the
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VAV-SVX07B-EN
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