Economizer control (optional) - Verasys - LIT-12013067 - LC-IOM3711-0 - LC-VAC1000-0 - LC-VAC3000-0 - Field Device - Verasys Constant Volume Controller

Verasys Constant Volume Controller Application Note
Product
Controls > Field Controls > Verasys Constant Volume Controller
Document type
Application Note
Document number
LIT-12013067
Revision date
2023-04-27

You can configure an economizer with the following settings.

You can set the economizer damper type, from the System Configuration > Details menu. Use the following list to understand the available settings:

  • None - There is no economizer connected, or another device controls an economizer.
  • Min OA - The damper opens to a minimum position when the unit is in the occupied mode. MA-T low limit logic does not affect this position and it remains constant.
  • Economizer - The controller modulates the damper section when the outdoor air temperature is cooler than the economizer setpoint. The economizer acts as the initial stage of cooling and works in sequence with the cooling output.

In the Commissioning > Economizer menu, the low limit control is active when the Economizer Damper Type is set to Economizer and the low limit temperature is below the Low Limit Temp Setpoint. The Low Limit Temp Setpoint is either Mixed Air or Supply Air as dictated by Min OA Sensor.

Note: If the cooling coil control or heating coil control is proportional, this feature is not optional and requires a mixed-air sensor, not a supply air sensor. MA-T controls the MA-T low limit logic.

To set the option for demand control ventilation, navigate to Details > Sensors > CO2 Installed. Change the setting from Not Installed to one of the three following settings:

  • SAB sensor (ZN-Q)
  • Hardwired sensor (RA-Q)
  • Both

When you choose one of these settings, the sensors reset the damper minimum position as the CO2 sensor rises above the CO2 setpoint. If both sensors are installed, the hardwired sensor (RA-Q) takes priority.

Note: To configure the CO2 reset settings, navigate to the Commissioning > Economizer menu. The true minimum position output of the economizer spans between user-adjustable Minimum OA Percent and Min Pos High Setpoint based on the CO2 Reset A, CO2 Reset B, and measured CO2.