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DN-Series Integrated Programmable Controls
DOAS
7.0 UNOCCUPIED OPERATION
The DN DOAS unit can be ordered with an optional recirculation damper for unoccupied
operation. The occupied/unoccupied signal can be set from the BMS or the scheduler.
During unoccupied operation, the unit allows the run the supply fan to run as set, and the heat
or cool based on unoccupied setpoints for return air. This ensures that the temperatures do not
go too far away from setpoint when the unit is unoccupied. To enable this feature, the unit must
have recirculation dampers and the feature enabled here.
The settings for control are:
u
Fan On: Continuous or Heat or Cool. If continuous, the fan will run all of the time at the low
CFM in the next setting. If Heat or Cool, the fan will only run on a call for heat or cool.
u
Flow Rate: The fan will run as specified to maintain this flow rate.
u
Heating below: The heating will run if the return air is below this temperature.
u
Cooling above: The cooling will run if the return air is above this temperature.
The unit can also be set to perform dehumidification, using the same dehumidification
setpoints, in unoccupied mode if there is a humidity load in the space.
NOTE: This control
is usually used for
systems that feed
one space and have
no additional tempering in
the space. The control for
unoccupied operation is
based on RA. Since there
is no airflow the RA sensor
is not indicative of the
room temperature. In this
case it is possible to use
a room temperature and
humidity sensor instead
of the RA temperature
and humidity sensor. See
the
Use Room Temp and
Humidity Rather Than
Return
section in
Special
Features
for
more information.
8.0 SPECIAL FEATURES
These features are not common but are available in the DN DOAS controller.
8.1 FROST CONTROL
DN DOAS units utilize the bypass damper to bypass the core when it is very cold outside. This is
usually used in northern states and Canada. The function is enabled in this screen.
UNOCCUPIED OPERATION