LX Series Unit Ventilator Controller User's Guide
39
Selecting Fresh Air Damper Control for Ventilation Only
(without Free Cooling)
The Fresh Air Damper is closed during unoccupied periods. This diagram shows
damper control during:
Standby, Occupied and Bypass Modes; or,
Occupied Mode when free cooling is not in use or is disabled. Free cooling is not
in use whenever the free cooling output is less than minimum fresh air output.
Fresh_Air_Damper_Mod
Proportional Control
Min_Fresh_Air_Enable
Fresh air minimum
input
CO2 PID
Control
SCPTlimitCO2
Select the
Greatest
MAT Low Limit or SAT
Min Supply Temp.
CO2 Sensor Value
or
nviCO2
Select how the
Damper is controlled.
Can use either
of these two
outputs.
Ye
s
Fresh Air Damper
Is CO2 sensor
present?
Is damper position set
as the Fresh Air
Minimum Input?
No
Ye
s
No
Percentage of
fresh air intake
MA
T
OAT
RAT
Fresh air minimum
input
MAT
Mixed Air Temperature
SAT
Supply Air Temperature
OAT
Outside Air Temperature
RAT
Return Air Temperature
Inputs to PID Control
Inputs to Proportional Control
UCPTminOutdoorAir
Is no limitation on
fresh air intake is
checked?
Ye
s
SAT Min Supply Temp.
No
vent
Figure 15: Ventilation Process