Product Overview

BAC-1xx63/1xxx63 Series (6 Relays and 3 Analog Outputs) Section 50 Application Guide S
3. During STANDBY mode, the outside damper shall be closed.
4. Upon leaving STANDBY mode and returning to NORMAL, the ac-
tive heating and cooling setpoints return to normal following the
same 1° F per 15 minute rate as described in the Standby mode se-
quence described above. Fan O Timer resumes incrementing as nor-
mal.
The following DCV modes apply during Unoccupied mode:
Unoccupied Off
If Unocc Fan mode is set to AUTO, the supply fan shall be o except on
a call for heating, call for cooling or when operation is called for as de-
scribed below. Outside dampers shall remain closed when the fan is o.
Night Flush
Night Flush mode uses the economizer only to pre-cool the building,
subject to the following conditions:
1. Night ush is intended to be seasonal, but may switch more than
once during swing seasons. Night Flush Enable is ENABLED when
OAT exceeds 70° F (21.1° C) and remains enabled until OAT drops
below 45° F (7.2° C). It then remains disabled until OAT once again
exceeds 70° F (21.1° C).
2. Night Flush Mode will be ON when all the following conditions are
true:
a. Night Flush Enable is ENABLED as above.
b. OAT is less than Econ Enble Temp – 1° F (0.55° C).
c. Space Temp is greater than Occ Heating Setpt + Min Setpt Di.
d. The time is between midnight and the rst scheduled Occupied
start time.
3. Night Flush Mode stops when any of the following conditions are
true:
a. Night Flush Enable is DISABLED as above.
b. OAT is greater than Econ Enble Temp + 1° F (0.55° C).
c. Space Temp is less than Occ Heating Setpt + Min Setpt Di / 2.
d. The time is greater than the rst scheduled Occupied start time.
During Night Flush mode, Econ Mode is ENABLED and the fan is called
for to run.
NOTE: To permanently disable the night ush option, write Inactive at
priority 8 to BV40.
Ventilation Pre-Purge
If OA Purge (0% default) is greater than zero, during the 60 minutes
prior to the rst scheduled Occupied start time, the supply fan is called
for to run and the OA damper is set to OA Purge.
Dehumidification
On FlexStat models with a humidity sensor, dehumidication is oered
as an option. Once the dehumidication sequence is enabled through
the user interface, the dehumidication mode starts if the space humid-
ity rises above the dehum setpoint (adjustable, default 60%). The dehum
mode is stopped if the space humidity drops below the dehum setpoint
minus the dehum span (adjustable, default 5%). Dehumidication mode
being started also generates a call for fan if the fan mode is set to “Auto.”
Humidification (BAC-1x136 and BAC-1xx136 Only)
On BAC-1x136 and BAC-1xx136 models, humidication is oered as an
option. Once the humidication sequence is enabled through the U/I,
two other options are presented; humidier valve type and an option to
lockout the humidier sequence under certain conditions.
If “allow clg hum” is set to “no,” then the humidier valve is automati-
cally closed any time the FlexStat is operating in the cooling mode and
allowed to follow the normal humidier sequence if the FlexStat is in the
heating mode.
If “allow clg hum” is set to “yes” (default selection), then the humidier
valve follows the normal humidication sequence whether the unit is in
the heating or cooling mode.
If the humidier valve is set to modulating, then the humidier valve
will generally start to open as the space humidity drops below the
humidication setpoint and will modulate to fully open as the space hu-
midity falls below the humidication setpoint minus the humidity span.
Actual response may vary slightly due to PI action of the control loop.