Trane Tracer ZN521 Installation And Operation Manual page 54

Chapter 5 Sequence of operations
Table 9. Modulating outdoor air damper position setpoint determination
Occupancy
Unoccupied
Occupied
Occupied bypass
Occupied standby
Occupied
Occupied bypass
Occupied standby
Occupied
Occupied bypass
Occupied standby
Table 10. Relationship between outdoor temperature sensors and damper position
Outdoor air temperature
No or invalid outdoor air
temperature
Failed outdoor air sensor
Outdoor air temperature
present and economizing
1
possible
Outdoor air temperature
present and economizing
1
not possible
1
For an explanation of the economizing feature, see "Economizing (free cooling)" on page 45.
44
low-speed fan operation. A controller can also receive a BAS-communi-
cated outdoor air damper minimum position.
A BAS-communicated minimum position setpoint has priority over all
locally configured setpoints. When a communicated minimum position
setpoint is not present, the controller uses the configured minimum posi-
tion for low fan speed whenever the fan is running at low speed, regard-
less of the occupancy state. See Table 9 and Table 10 for more information
about how the controller determines the position of the modulating out-
door air damper.
BAS-communicated
setpoint
Any value
Valid
Invalid
Invalid
Invalid
Modulating outdoor air damper position
Occupied or occupied
bypass
Open to occupied
minimum position
Open to occupied
minimum position
Economizing; damper
controlled between
occupied minimum
position and 100%
Open to occupied mini-
mum position
Fan speed
Any value 0% (closed)
Any value BAS-communicated
Low Occupied low fan minimum
Medium/high Occupied minimum
Medium/high Occupied standby minimum
Occupied standby
Open to occupied standby
minimum position
Open to occupied standby
minimum position
Economizing; damper
controlled between
occupied standby
minimum position and
100%
Open to occupied standby
minimum position
Active minimum setpoint
Unoccupied
Closed
Closed
Open and economizing
during unit operation; oth-
erwise closed
Closed
CNT-SVX07C-EN