Distech Controls ECB-VAVS - Page 37

37ECB-VAVS Preloaded Applications
Air Flow Calibration (VAV Balancing)
From the
Calibration
subsection, the VAV airflow balancing procedure can be carried out.
Figure24: Calibration Subsection
Parameter Description
K-Factor The actual flow required to generate 1” WC (in CFM) or 1 Pa (in L/s).
Flow Calibration
The actual flow. When the value is sent to the VAV controller, the controller will
automatically calibrate its flow reading and readjust the K-Factor.
Balancing Override
The balancing override setting. Different values can be selected: normal, minimum flow,
minimum flow heat, minimum flow cool, 75% maximum flow, 80% maximum flow, 85%
maximum flow, 90% maximum flow, 95% maximum flow, damper full open, damper full
close, and damper initialization.
Flow Setpoint Displays the actual flow setpoint (read-only).
Flow Status Displays the airflow status.
The following steps outline the procedure for balancing a VAV controller:
1. Enter the VAV box’s K-Factor.
The K-Factor can be acquired from the VAV box manufacturer. The table below shows what the K-
Factor represents in both Imperial and SI Units.
Units What the K-Factor represents
Imperial Airflow (in cfm) at 1” WC
SI Airflow (L/s) at 1 Pa Airflow (m
3
/h) at 1 Pa
2. Override the flow setpoint. To do so, click the Edit button next to the Flow Setpoint on the EC-
Net 4 configuration PX page and modify it by selecting a relatively high setpoint. You can also
modify it using the Balancing Override setting to automatically set the flow setpoint to a prede-
fined flow. Monitor the current flow until it stabilizes.
3. Using a flow hood, measure the actual airflow. Enter this measurement in the box beside Flow Cal-
ibration. The K-Factor gets adjusted based on the airflow value just entered.
4. Release the flow setpoint override by clicking the Edit button beside Flow Setpoint on the EC-Net 4
configuration PX page. Alternatively, return the Balancing Override setting to Normal Operation.
At this point, the VAV controller is balanced. The adjusted K-Factor can be included in the balancing
report.
Using the dc gfxApplications