Using the Commission mobile application, you flow balance a VAV unit at each designated setpoint to achieve the desired air flow.
You can select one, two, or three flow setpoints for flow balancing. The minimum flow setpoint is selected by default. In addition, you can also select the intermediate flow setpoint.
In the Air Balancing Setpoints view, the Intermediate flow setpoint check box is cleared by default. However, it is recommended that you include this setpoint for flow balancing. While the maximum setpoint does not have a check-box, it is still mandatory that you include that setpoint too. Doing so allows you to achieve greater flow accuracy across the operating flow range of the VAV unit.
In the Commission mobile application, on the Device Settings page, click Flow Balancing .
In the Air Balancing Setpoints page, notice the checkbox next to the Minimum flow box.
Enter setpoint values for the Minimum flow , Intermediate flow , Maximum flow and click Next .
The Commission mobile application issues a message and then checks to ensure that the damper is in the closed position before calculating the velocity pressure offset . If it is not currently closed, it waits to close.
The offset is calculated at this point in the flow balance process to address any potentially significant velocity pressure zero offset errors. Such errors may interfere with flow control near minimum flow setpoints.
The velocity pressure offset is then calculated by averaging 20 sample readings.
To skip the velocity pressure offset reading, click the Bypass velocity pressure offset box on the Setpoints page . If you have a large number of VAV boxes to balance, this process can be time-consuming, so you may wish bypass it as needed.
After the offset calculation is complete, click Yes to accept the change and write the value to the controller and proceed.
Click No to disregard the zero offset calculation.
The application now goes ahead and calculates the minimum, intermediate, and maximum flow setpoints.
Once those calculations are complete, the VAV unit is flow balanced at the selected setpoints. Now you are ready to perform manual checkout.