Delta Controls
Document Edition 4.1
Page 15 of 41
3.
B
OX
M
ODE
(DNT-T103
AND
DNT-T221
O
NLY
)
When the application control strategy is configured for VAV or VVT, the Box Mode (variable AV33)
can be set to either cooling (default) or heating. When set to cooling, the air supply is treated as the first
stage of cooling. When set to heating, the cooling controller is inverted and the air supply is treated as
the first stage of heating.
Box Mode
Description
AV33
Cooling
Duct Supply Air to the box provides cooling (default)
0
Heating
Duct Supply Air to the box provides heating
1
This variable cannot be commanded or changed from the BACstat. As this function is completely
dependent on the air supplied to the boxes from another source, this variable would normally be
commanded over the network (i.e., typically via GCL+) whenever the air system changes between
heating and cooling.
N
OTE
:
As of Release 3, VAV and VVT applications can no longer be configured with more than 1
stage of cooling. In earlier releases of firmware, do not configure a BACstat with more than 1 stage of
cooling, as additional stages of cooling don’t work properly when
Box Mode
is ever set to heating.
Software Controller Loop
1.
G
ENERAL
The operation of the BACstat II is centered around a software controller. The controller uses the
following parameters in its operation.
Parameter
Object
Default Value
Notes
Room Temperature
AI1
N/A
Input 1 **
Temperature Setpoint*
O
CCUPIED
: Uses Day Setpoint (AV6)
U
NOCCUPIED
: Uses Night Heat Setpoint
(AV10) if the Input is below the Night Heat
Setpoint (AV6); and uses the Night Cool
Setpoint (AV11) if the Input is above the Night
Cool Setpoint (AV6); otherwise it is in a null
zone.
Proportional Band
AV19
2.0 ºF / 1.0 ºC
Degrees F or C as configured for AI1
Reset Rate
AV20
1.0
Resets per hour
Day Differential
AV9
1.0 ºF / 0.5 ºC
Degrees F or C as configured for AI1
* Humidity Setpoint if operating as a Humidity controller
** Input 3 (AI3) if operating as a
Humidity controller
