Balancing a Single Duct SimplyVAV Controller
The balancing routine is part of the programming in every SimplyVAV controller. Only the following items are required for balancing.
- A SimplyVAV digital sensor to use as a configuration tool. If another type of sensor is installed as the room sensor, temporarily connect an STE-8001 as a service tool.
- An airflow hood or other precision instrument to measure airflow
- The minimum and maximum airflow limits for each VAV terminal unit
Begin airflow balancing
- Set up the controller with all temperature and airflow setpoints and limits.
- Start balancing by pressing and holding the UP and DOWN arrow buttons on the SimplyVAV digital sensor at the same time.
- If Password 2 is not required, the display changes to the CNFG for configuration.
- If required, enter Password 2. The display changes to CNFG when Password 2 is correct.
- From the configuration display, press the UP arrow button to display BLNC.
- Press the SETPOINT button.
- When the display advances to PRI press SETPOINT again. This starts the balancing routine. Once the balancing routine starts, all other functions of the controller are locked out and the controller drives the damper open until the airflow reaches the highest value of either the cooling or heating maximum airflow setpoints. The display flashes PMAX during this phase.
- When the airflow reading stabilizes, as shown in the small numbers at the bottom of the display, measure the airflow with an airflow hood and make note of the actual flow measurement.
- Press SETPOINT and PMAX will stop flashing and the small numbers at the bottom will start flashing. Use the UP and DOWN buttons to enter the actual airflow value you measured with the flow hood.
- Press SETPOINT to save the value and advance to the PMIN display. Similar to PMAX, the controller drives the damper closed to the lower value of either the cooling or heating minimum airflow. The display flashes PMIN and shows the airflow at the bottom of the display.
- When the airflow reading stabilizes, as shown in the small numbers at the bottom of the display, measure the airflow with an airflow hood and make note of the actual flow.
- Press SETPOINT and PMIN will stop flashing and the small numbers at the bottom will start flashing. Use the UP and DOWN buttons to enter the actual airflow value you measured with the flow hood.
- When the entry is correct, press SETPOINT. This saves the PMIN value and returns the controller to normal operation.
After the minimum airflow measurement is entered, the programming in the controller calculates airflow correction factors which are used to adjust measurements from the internal airflow sensor.
For dual-duct VAV installations, you have to also balance the airflow in the secondary controller which follows the same procedure.