028-0506-02_II-VZ8250_EN www.viconics.com
January 2020
16
VZ8250
[
Installation Guide
]
The recommended process for Balancing the system is:
1. On page “1/2 Balancing (PI)”, check the Minimum, Maximum Cooling, Maximum Heating and Reheat airflow setpoints are
correctly configured for the zone.
2. Check airflow sensor is correctly zeroed:
a. On page “2/2 Balancing (PI)”, set Damper Override to Close.
b. Wait for measured “Airflow level” to stabilize and confirm the value is less than the desired Minimum Airflow. If not, confirm
damper is closed and auto-zero the airflow sensor. Refer to the flow sensor Installation Guide for more information on
zeroing.
3. Before setting the Minimum and Maximum Cooling airflow, make sure that when fully open, the airflow is at least 40-60 CFM
higher than the planned Maximum Cooling airflow. Otherwise, the control will be erratic.
NOTICE
MINIMUM AND MAXIMUM COOLING AIRFLOW
When damper is fully open, the airflow must be at least 40-60 CFM higher than the planned Maximum Cooling airflow.
Failure to follow these instructions can result in erratic airflow control depending on the HVAC design.
4. Calibrate sensor at Minimum airflow:
a. On page “2/2 Balancing (PI)”, set the Damper Override to Minimum Flow. The displayed Airflow Setpoint will use the value
of Minimum Airflow.
b. Wait for the Room Controller measured “Airflow level” to stabilize.
c. Take a reading of the actual airflow using a calibrated Balometer.
d. Enter the actual airflow as the “Balometer” value on “2/2 Balancing (PI)”. The Room Controller will calculate and display a
new Minimum Flow Offset.
e. Wait for the measured “Airflow level” to stabilize again. The Airflow level should now match the Airflow setpoint. Repeat if
necessary.
5. Calibrate sensor at Maximum Cooling airflow:
a. On page “2/2 Balancing (PI)”, set the Damper Override to Maximum Cooling. The displayed Airflow Setpoint will use the
value of Maximum Cooling Airflow.
b. Wait for Room Controller measured “Airflow level” to stabilize.
c. Take reading of actual airflow using a calibrated Balometer.
d. Enter the actual airflow as the “Balometer” value on “2/2 Balancing (PI)”.
e. The Room Controller will calculate and display a new Maximum Flow Offset.
f.
Wait for the measured “Airflow level” to stabilize again. Airflow level should now match the Airflow setpoint. Repeat if
necessary.
6. On page “2/2 Balancing”, revert the Damper Override to None allowing the system to return to normal operation.