Installation and Maintenance Manual

50 VAV-SVX07A-EN
Tracer™ UC400 Controller Operations
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 testing, adjusting, and balancing professional will use the TU Service Air and
Water Balancing tool to calculate this value and balance the VAV box. Normally, you should not
need to change this value here.
Minimum AirFlow Delta: The minimum amount of change in the primary airflow required before
airflow and the airflow setpoint are communicated on the communication link. The percentage of
change required is based on the nominal airflow. For example, if the nominal airflow is 1000 cfm
and the minimum delta is 2%, the primary airflow must increase or decrease by 20 cfm before the
change is communicated on the communication link.
Ventilation Setup
Ventilation Setpoint BAS: The Tracer Summit™ 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.
Space CO
2
Setup
Low Limit: The controller adjusts the ventilation setpoint only when the CO
2
concentration falls
within the high and low limits. When the CO
2
concentration falls below the low limit, this indicates
that the zone is most likely unoccupied and that a minimum of ventilation air is required to ventilate
the zone.
High Limit: The controller adjusts the ventilation setpoint only when the CO
2
concentration falls
within the high and low limits. When the CO
2
concentration rises above the 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.
Flow Setpoints Setup
Minimum Airflow: 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.
Maximum: This range is 10% to 100% of the unit's cataloged 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. It can be activated for a
classroom currently not in use. Standby Minimum is the minimum amount of airflow desired
during this mode.
Standby Heating Minimum Airflow: Occupied standby mode is used to reduce the heating and
cooling demands during the occupied hours when the space is unoccupied. It can be activated for
a classroom currently not in use. Standby Heating Minimum is the minimum amount of airflow
desired when in the heat mode during this mode.
Heating Minimum Airflow: 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.
Heating Maximum Airflow: The controller enters maximum flow heat on receipt of a
communicated command and remains in maximum flow heat until the command changes. The