Air Valve Control In Flow Tracking Control Operation; Reheat Control In Flow Tracking Control Operation; Unoccupied Flow Tracking Control - Trane Tracer VV550 Installation, Operation And Maintenance Manual

Table 44.Flow tracking control required inputs
Communicated Calibration
airflow setpoint
Invalid Do not care
Do not care Failed
Do not care Do not care
Valid Not failed
If the calculated airflow setpoint is less than 10% of the configured nominal airflow and
the configured airflow tracking offset is less than zero, the air valve is closed. If the
calculated airflow setpoint is less than 10% of the configured nominal airflow and the
configured airflow tracking offset is greater than or equal to zero, the air valve is
positioned at the configured minimum airflow. The maximum airflow setpoint is limited
by the configured maximum airflow.

Air Valve Control in Flow Tracking Control Operation

The Tracer
cooling operation. Air delivered to the space is controlled with a three-wire floating-point
actuator that modulates the air valve. The controller positions the modulating air valve
to deliver the desired airflow (cooling or heating capacity). The desired airflow is called
the active flow setpoint.
Flow tracking control is provided by two controllers working together: space temperature
controller and flow tracking controller. The space temperature controller outputs the
airflow as reported airflow. The airflow is determined by the airflow setpoint input
(communicated airflow setpoint) of the flow tracking controller. The flow tracking
controller adds a configured airflow tracking offset (positive or negative) to the
communicated airflow setpoint and controls its airflow to this new airflow setpoint.

Reheat Control in Flow Tracking Control Operation

Reheat is not an option on a flow tracking controller.

Unoccupied Flow Tracking Control

In unoccupied control mode, the controller operates the air valve the same as it does in
occupied control mode. The controller enters this mode from a communicated command
or from a local occupancy sensor.
CNT-SVX17G-EN
Airflow sensor
Do not care
Do not care
Failed
Not failed
®
VV550/VV551 controllers support one modulating air valve for heating and
Configured airflow Air valve position
tracking offset
< 0 Closed
> 0 Configured maximum airflow
< 0 Closed
> 0 Configured maximum airflow
< 0 Closed
> 0 Configured maximum airflow
< 0 Modulated between closed and the
configured maximum airflow
> 0 Modulated between the configured
minimum airflow and the configured
maximum airflow
Sequence of Operations
71