Trane Zone Controller, N512, CNT-SVX07C-EN manual Modulating outdoor air damper position

Chapter 5 Sequence of operations

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.

Table 9. Modulating outdoor air damper position setpoint determination

Occupancy	BAS-communicated	Fan speed	Active minimum setpoint
	setpoint
Unoccupied	Any value	Any value	0% (closed)
Occupied	Valid	Any value	BAS-communicated
Occupied bypass
Occupied standby
Occupied	Invalid	Low	Occupied low fan minimum
Occupied bypass
Occupied standby
Occupied	Invalid	Medium/high	Occupied minimum
Occupied bypass
Occupied standby	Invalid	Medium/high	Occupied standby minimum

Table 10. Relationship between outdoor temperature sensors and damper position

	Modulating outdoor air damper position
Outdoor air temperature	Occupied or occupied	Occupied standby	Unoccupied
	bypass
No or invalid outdoor air	Open to occupied	Open to occupied standby	Closed
temperature	minimum position	minimum position
Failed outdoor air sensor	Open to occupied	Open to occupied standby	Closed
	minimum position	minimum position
Outdoor air temperature	Economizing; damper	Economizing; damper	Open and economizing
present and economizing	controlled between	controlled between	during unit operation; oth-
possible1	occupied minimum	occupied standby	erwise closed
	position and 100%	minimum position and
		100%
Outdoor air temperature	Open to occupied mini-	Open to occupied standby	Closed
present and economizing	mum position	minimum position
not possible1

1For an explanation of the economizing feature, see “Economizing (free cooling)” on page 45.

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