CVAHU Economizer

Description

Economizer settings for CVAHU application.

Purpose

Define the four settings for using an economizer.

Mode

Off-line or On-line

Procedure

  1. Click the Economizer button on the left pane to open the Economizer Configuration page.
  2. Enter information into available fields.
  3. Select the Enable Type for the economizer.
  4. Use the Min Position field to select a Minimum Position for the Outdoor damper.
  5. Use the IAQ Position field to select a minimum damper position for poor Indoor Air Quality (IAQ) conditions.
  6. Use the Use Heat for IAQ field to choose whether or not to use heat during poor Indoor Air Quality conditons.
  7. Click Commit to save the settings or Reset to revert to the last saved settings.
  8. Click Next to display the Heat-cool Stages Configuration page or Back to display the Equipment Control Configuration page.

Fields           

Name Definition
Enable Type Source of the economizer enable decision for determining when to use outdoor air for cooling. The list of available selections is:
  • NoLocalEconSensor
  • OutdoorTemp
  • DiffTemp
  • OdEnthTypeA
  • OdEnthTypeB
  • OdEnthTypeC
  • OdEnthTypeD
  • SingleEnthalpy
  • DiffEnthalpy
  • Digital

The W7750A will have the following options only:

  • NoLocalEconSensor
  • OutdoorTemp
  • Digital
Min. Position Minimum position of the Outdoor Damper (0 to 100 percent). Under normal Occupied-mode operation, the dampers are not closed below this setting. If Unoccupied, or if a Discharge Low Temperature condition exists, the dampers are closed below this setting.
IAQ Position Minimum Position of Damper used when poor Indoor Air Quality conditions exist (IAQ sensor>IAQ Setpoint, or if Digital IAQ Switch is on). Select a value from 0 to 100 percent.
Use Heat for IAQ Enable or disable heat.
  • Yes enables heat when damper is open for IAQ purposes.
  • No disables heat if controller is in Cool mode.

NOTE

A discharge low temperature condition overrides this setting and closes the dampers to prevent equipment damage due to freezing.
Enable Setpoint It defines the setpoint value for enabling the economizer
OA Temp High Limit It defines the high limit for the Outside temperature

Back