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CVAHU Economizer
Purpose
Define the four settings for using an economizer in a CVAHU
application.
Mode
Configuration can be performed with the wizard 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 conditions.
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.
CVAHU Economizer fields
Table 22 lists the CVAHU Economizer fields.
CVAHU HC Stages
Description
The minimum on/off times, Cycles/ hour, Minimum and
maximum recovery ramps are set for heating and cooling
stages of a CVAHU application.
Purpose
Define heating and cooling (h/c) stage parameters, including
minimum on and off times.
Mode
Configuration can be performed with the wizard Off-line or
On-line.
Procedure
1. Click the H/C Stages button on the left pane to open the
Heat-Cool Stages Configuration page.
2. Select MinHeatOn/Off for Heating and MinCoolOn/Off
for Cooling.
3. Enter information into available fields.
4. Click Commit to save the settings or Reset to revert to
the last saved settings.
5. Click Next to display the Zone Options Configuration
page or Back to display the Economizer Parameters
Configuration page.
Table 22. CVAHU Economizer 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 Defines the setpoint value for enabling
the economizer.
OA Temp High
Limit
Defines the high limit for the outside
temperature.
Table 22. CVAHU Economizer Fields. (Continued)
Name Definition