WEBVISION™
95-7769—01
78
UV Heating/Cooling (H/C) Stages
Use Table 57 to configure the Unit Ventilator H/C Stages to set
the minimum on/off times, Cycles/ hour, recovery ramps of a
Unit Vent application for heating and cooling stages.
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
HcStageParameter
button on the left pane to
open the
H/C Stage Parameters Configuration
page.
2.
Enter information into available fields.
3.
Click
Commit
to save the settings or
Reset
to revert to
the last saved settings.
4.
Click
Next
to display the
Zone Operations
Configuration
page or
Back
to display the
Economizer Configuration
page.
UV Heating/Cooling (H/C) Stages parameters
OA Damper Min
Pos
Minimum position of the Outdoor Damper
(0 to 100%). 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). Value range from 0 to
100%.
NOTE: A discharge low temperature
condition overrides this setting
and closes the dampers to
prevent equipment damage due
to freezing.
Use Heat for IAQ Select one of the following options:
•
Yes - Enables heat to be used when
the damper is opened for IAQ
purposes.
•
No - Keeps heat disabled if controller is
in Cool mode.
Oa Temp High
Limit
This field is enabled only when Enable
Type is set to Single Enth(alpy). It
provides an outdoor air temperature high
limit setting, above which, the economizer
is disabled, regardless of the current
enthalpy value.
Mixed Temp
Setpoint
(ASHRAE Cycle
3 only)
This field is enabled only when ASHRAE
Cycle III is selected in the Equipment
Control Tab.
Ashrae Cycle
When a unit ventilator is in the occupied
mode it typically follows one of three
operating cycles defined by the American
Society of Heating, Refrigeration and Air-
Conditioning Engineers, Inc. (ASHRAE):
•
Cycle I: Fixed 100% Outdoor Air
•
Cycle II: Variable Percentage of
Outdoor Air with Minimum Position
setting
•
Cycle III: Variable Outdoor Air
Maintaining Constant Mixed Air
Temperature
Enable Setpoint
OaEconEnTemp
DiffEconEnTemp
OaEnthEn
This setpoint is enabled if Enable Type is
Outside Air Temp, Diff. Temp, or Single
Enth
For OdTemp, this field sets the threshold.
The economizer is disabled when
OdTemp exceeds this value.
For Diff Temp, this field sets the difference
between the Outdoor and Return air
temperatures, above which, the
economizer is disabled.
For Single Enth, this field sets the
enthalpy value, above which, the
economizer is disabled.
Table 56. Unit Ventilator Economizer Settings. (Continued)
Name
Definition
Table 57. Unit Ventilator Heating and Cooling Stage
Parameters.
Name
Definition
Min On/Off
•
Min_heat_on enables minimum on/off
times.
•
Min_heat_off replaces set minimum
on/off times with a 30 second default.
•
Min_cool_on enables minimum on/off
times.
•
Min_cool_off replaces set minimum
on/off times with a 30 second default.
Cycles/Hour
Cycles per hour (cph). Enter value from 2
through 12. For example, cph for
conventional heating stage one is
normally 3 cph. Consult your hardware
installation guide for recommended
values.
Oa Temp Lock Out OA temperature lockout. OA temperature
values below the cooling lockout setting
disables the cooling stages. OA
temperature values above the heating
lockout setting disable the heating
stages.
Ramp
Recovery ramp (degrees per hour). Enter
value from 2 through 20 for cooling or 3
through 20 for heating
Fan Run-On Time Enter amount of time (from 0 to 120
seconds) the fan will continue to run after
the last stage of heating or cooling has
switched off.
This value is only applicable during
unoccupied times, and during occupied
times if the Fan Control field is set to
Auto_Fan.
