McQuay IM 846
9
Optional Occupancy Detection Equipment Operation
Optional Occupancy Detection Equipment Operation
The T170 thermostat can be used with optional S200 series
occupancy detection equipment. Purchasing and installing this
equipment to compliment the thermostat adds energy savings
by setting back HVAC operation during occupied and
unoccupied times. Optional detection equipment
configurations and operation are described below.
SB200-001 Occupancy Sensor
The SB200-001 occupancy sensor (Figure 10) serves as an
occupancy sensor for automatic control of a guest room HVAC
system. It incorporates an innovative dual delay processor
which allows the sensor to verify the nature of occupancies,
and is capable of eliminating unnecessary actuations of the
HVAC device due to unintentional passages or short time
occupancies. The sensor may also serve as a slave sensor
(Figure 11 on page 10).
The sensor switch is open in occupied mode and closed in
unoccupied mode. An optional door and/or window switch
(Figure 10) is open when the door/window is open and is
closed when the door/window is closed.
Note –
To use this configuration, a jumper must be installed to
JP3 to allow occupancy input.
Note –
An optional door and/or window switch (Figure 10) can be
added for use with the SB200-001 sensor.
Operation
In an occupied mode, the thermostat operates normally and
looks for a door open signal. When the door opens, the
thermostat waits for a door close signal. If the door is open for
more than two minutes, the thermostat turns the HVAC system
outputs to OFF. During this two minute period, if any button is
pressed on the keypad, the time delay is extended to ten
minutes. The time delay can only be extended once. Once the
HVAC outputs transition to OFF, a door closure is required to
re-enable the outputs. When the door closes, the thermostat
starts a two minute timer and tries to detect occupancy. If the
timer expires and no occupancy is detected, the thermostat
transitions to an unoccupied state. If occupancy is detected
while the timer is running, the thermostat will remain in the
occupied mode.
In an unoccupied mode, the thermostat sets heating and
cooling set points to setback values as determined by factory
or user settings. The fan is automatically set to cycle with
demand. The thermostat continually monitors the occupancy
sensor and will enter into occupied mode if occupancy is
detected.
If the installation is only using a door/window switch, the
thermostat will disable the HVAC outputs if this output is open
for longer than two minutes.
To enable door/window switch only operation, install a jumper
to JP3 (see “Mounting and Wiring the Thermostat” on page 3)
and the occupancy input must be shorted to circuit common.
Figure 10: Optional equipment configuration #1
