Product Overview

BAC-1xx63/1xxx63 Series (6 Relays and 3 Analog Outputs) Section 51 Application Guide S
If the humidier valve is set to two-position, then the humidier valve
opens if the space humidity falls below the space humidity setpoint and
closes if the space humidity rises above the space humidity setpoint plus
the humidity span.
The humidier valve closes any time the fan status is determined to be
“o.”
Staged Heating and Cooling Parameters
On applications with staged heating and cooling, there will be a 3 min-
ute (adjustable) delay between calls for stages (stage delay).
Once a stage of heating or cooling turns o, there is a 3 minute (adjust-
able) minimum o time before that stages output can be reenergized.
Once all stages of heating and cooling have turned o, the fan will re-
main energized for 3 minutes (adjustable, o delay).
User Interface Display Backlight
The user interface display backlight will illuminate any time any buon
is pushed on the FlexStat. It will remain illuminated for 60 seconds (ad-
justable). The display is also controllable from Control Basic program-
ming.
BAC-1xx63/1xxx63 Applications
AHU (Air Handling Unit)
Fan Control
The fan follows the base sequence for fan operation as listed in the Flex-
Stat (All Models) Common Features section above.
Valve Control
The method of controlling the heating and cooling valves is based on the
fan conguration:
• If the fan mode for a particular occupancy mode is set to con-
stant or “On,” the valves function in a modulating fashion.
Actual response may vary slightly due to PI action of the control
loops, but generally the heating valve will start to open as the
space temperature drops below the active heating setpoint and
modulate to fully open when space temperature reaches active
heating setpoint minus heating proportional band. Likewise, the
cooling valve will generally begin opening as the space tempera-
ture rises above the active cooling setpoint and be fully open by
the time the space temp reaches the active cooling setpoint plus
cooling proportional band, modulating linearly in between.
• With the fan mode set to “Auto,” the heating valve will open
100% if the space temperature falls below active heating setpoint
minus heating proportional band and fully close when space
temp rises above active heating setpoint. The cooling valve simi-
larly opens 100% if the space temp rises above the active cooling
setpoint plus cooling proportional band and fully closes if the
space temp falls below the active cooling setpoint.
If at any time there is a low limit alarm, the cooling valve is forced
closed and the heating valve opens fully.
If at any time there is a fan failure alarm, the cooling and heating
valves are both forced closed.