KMC Controls BAC-4000 series, Installation, Operation, And Application Manual

Page: 69 / 128

BACnet priority 5. The fan output remains enabled until the fan status switch
opens. The state of fan status is stored in a binary variable. See the topic
Value
objects on page 117
for variable object details.
When the fan is functioning normally and the fan status switch is open the
DAT input is normal temperature sensing input. When the fan status switch is
closed, the value for the DAT input is greater than 260. See the topic
Temperature sensing inputs on page 69
.
Display blanking
and backlight
The AppStat display and backlight can be set to take any of the following
actions one minute after the last button is pushed.
Display an analog clock instead of the temperature display.
Dim the display to a preset level.
Remain unchanged.
When the display is dimmed or the clock is visible, the display returns to
normal when any button is pushed. See the topic
Advanced options on page 60
for the procedure to change the display.
Temperature
sensing inputs
The AppStat includes inputs for sensing space, discharge air, fan coil unit
supply water, and outside air temperature.
Space temperature sensing
All models of AppStat include an internal temperature sensor for measuring
space temperature. For remote temperature sensing, an external, 10,000 ohm,
Type II thermistor sensor can be connected to terminals RS. If the AppStat
detects that a remote sensor is connected, the internal sensor is not used for
determining space temperature. See the topics
Input objects on page 114
and
Value objects on page 117 for object details.
Outside air temperature sensing
The outside air temperature (OAT) input is a required input for compressor
lockout and economizer applications and is an optional input for others. The
AppStat is configured for a Type III thermistor sensor to monitor outside air
temperature. The outside air temperature is also stored in an analog value
object. See the topics
Input objects on page 114 and Value objects on page 117
for object details.
Water temperature sensor
The Water Temperature Sensor input (WST) is a required sensor for two-pipe
fan coil units and is optional for other fan coil applications. The AppStat is
configured for a Type III thermistor sensor to monitor water temperature.
The water temperature can be monitored as an analog input and is also
Installation, Operation, and Application Guide for AppStat Section 5: Sequences of operation
Revision G 69